Inside the Creation of Tilly Norwood, the AI Actress Freaking Out Hollywood

Van der Velden shared her vision with ChatGPT, typing out a short description of her ideal candidate: “A stunning female celebrity with global appeal. She has symmetrical facial features, clear radiant skin, and captivating green eyes. Her hair is long.”

Out came the first image of Tilly—cartoonish, with pouffy lips, kiwi-colored eyes and vague ethnicity. ChatGPT, perhaps drawing on data showing that there are far more dark-haired people in the world than blondes, decided to make her a brunette. Van der Velden, who is blonde and blue-eyed, took the note.

Every time she told AI to refine the face, a different one emerged. Tilly’s new brown eyes were good, but then she had weird buck teeth. In one version, she looked no older than 14. In another, her eyelashes evoked those of a llama. Then her face looked like it had been dipped in melted butter. There were too many Tillys, none of them right. She was either too perfect or too sexy or too plastic or had too many heads (three). Her creator wanted a realistic girl next door, an English rose. 

“I’ve grown up in this world,” said Van der Velden, 39, a former actress who spent her early 20s trying to make it in Hollywood. “I know what type of girl they would cast.” 

Over the next six months, Van der Velden toiled with her 15-person team to nail down the look of her leading lady, creating 2,000 iterations of an actress unbound by the limits of physical ability, age or talent. She passed on dud iterations with the ruthless efficiency of a casting director who makes actors cry at auditions. “I was really looking for the X factor,” she said. When she finally found her Tilly, it hardly mattered that the ingénue showed up with half her forehead missing. “This was the magic moment.”

When Van der Velden told a Zurich Film Festival panel in September that talent agencies were vying to represent Tilly, the character went viral, and not in the way her creator would’ve hoped. (Tilly was originally introduced in a social media video over the summer.) Hollywood actors, directors and their unions railed against her—or “it,” as some called her—saying the synthetic performer had the potential to ruin the livelihoods of real cast and crew while eroding the art of cinema itself.

“Avatar” director James Cameron called the likes of Tilly “horrifying.” Guillermo del Toro, director of “Frankenstein,” said he’d “rather die” than make a movie with AI. Actual human movie star George Clooney predicted a hard road ahead for Tilly types, saying: “AI is going to have the same problem that we have in Hollywood, which is, making a star is not so easy.” 

Actress Emily Blunt took one look at Tilly and blanched. “Good Lord,” she said, “we’re screwed.”

Van der Velden has been taken aback by the severity of the anti-Tilly sentiment in an industry with which she’s often felt a kinship. She moved to the United Kingdom at 14, leaving her home on the Dutch island of Curaçao with dreams of becoming an actress. The child of a Dutch executive and an artist, she enrolled at Tring Park School for the Performing Arts, whose famous alumni include Lily James and Daisy Ridley. 

Long drawn to science, she earned her undergraduate and masters degrees in physics at London’s Imperial College. But soon she was back at performing, landing work on Dutch TV. During a trip to Los Angeles, an agent told her she could be the next Blake Lively if she lost 10 pounds and paid more attention to her looks. She responded by creating a buffoonish beauty-queen character for a BBC Three web series, “Miss Holland.” In a typical scene, Miss Holland, played by Van der Velden with milkmaid braids and hairy armpits, chokes on the aerosol of a spray tan.  

The producer Eline Van der Velden, the creator of AI actress Tilly Norwood, toiled with her 15-person team to nail down her look. Eline Van der Velden/Particle 6

After she reaped more than $100,000 from the sale of a small business in which she was a minor shareholder, the producer, then 27, launched a London-based production company that would eventually be called Particle6. She gave herself one year to make it work. Soon she was creating short skits for BBC Three and YouTube, comic gambits like getting bikini-clad sunbathers to put on clothes or standing too close to strangers to see what would happen.

When AI started booming, she was quick to embrace it. She gave her administrative tasks to ChatGPT, which she called her “s— intern.” Last year, Sora, the generative AI tool that turns text into video, opened her eyes to opportunity. 

“I was blown away by the artistry and the poetry of it all,” she said. Noticing a budding cast of AI influencers, she figured AI screen stars were next. Some stylized AI celebrities existed, like the robot personality Lil Miquela, but Van der Velden wanted a commercially available actress who looked like a real person. She’d created characters before. She’d do it again.

Van der Velden says she is not out to replace real actresses. She is after something else—a new visual language of acid-trippy world building and uncanny realism only made possible by AI. She envisions “a whole new creative renaissance” for filmmakers and fewer financial barriers to new work. Most big movies today cost more than $100 million to make. Van der Velden thinks one done with AI would cost a fraction of that. 

Whether AI will actually cut costs for companies is a hotly debated topic, in part because the technology is so expensive. So far, mainstream Hollywood is open to the use of AI for technical production but not core creative tasks. 

Despite the outward tumult over AI, Van der Velden said the reception has been warmer behind closed doors. In recent weeks, she has signed about 60 nondisclosure agreements for hybrid movies (with real actors), full AI films and Tilly-specific projects, most of them in the $10 million to $50 million range. She self-funded the work on Tilly, spending more than $60,000 to launch an offshoot company that would go on to build the character. Van der Velden is a majority shareholder in Particle6, which she says has been profitable for the last decade.

From the start, ChatGPT was full of ideas when asked about Tilly’s creation: “Maintain excellent grooming, nutrition, and fitness,” it told Van der Velden. Tilly should look energetic and healthy, it said, “without extreme modifications that might alienate parts of the global audience.” The AI ordered up “classic elegance with a modern twist” and a “cosmopolitan charisma” that would allow Tilly to, say, “adopt local fashion elements during an Asian press tour.” The actress could also make a political statement: ChatGPT noted that her ambiguous ethnicity “not only adds to global relatability but also aligns with modern ideals of inclusivity.”

As the team worked, Tilly gained freckles and a few extra pounds so she wouldn’t look too slight for an action movie. AI always seemed intent on giving her bushy eyebrows and slight bags under her eyes, to the surprise of select audiences at industry events who saw early snippets of Tilly. (“People often say, ‘Oh, she looks a bit tired,’” Van der Velden said.) In one rough video demo, Tilly showed up with a wedding ring on her finger, which men in particular seemed to notice. (She is single.)

“To a certain extent, it is random, it’s luck, and that’s why I think you need a lot of good, creative judgment and vision and taste,” Van der Velden said.  

The staff revised Tilly with image generators, dialing up her resolution, reproducing her face and placing her in varied settings using tools such as Whisk, Topaz, Veo 3, Higgsfield and Seedream.

Building her voice was no less challenging, especially when it came to tone and timbre. In one phase, she spoke with the grace of Peppa Pig, the British animated TV character, which was an obviously unacceptable result.

Tilly officially got her name in March. Van der Velden overruled a suggestion from ChatGPT, which wanted to call her Nova Lux. It also came up with Tilly Warner, which the staff helped workshop to Tilly Norwood. The team searched to make sure multiple Tilly Norwoods weren’t populating the real world. She’s 24, but she can be aged up or down depending on the role. 

The final Tilly emerged in May: messy hair, sheer top, kittenish smile. Keeping Tilly’s image consistent was challenging, but once the team figured that out they were able to turn her into a talking, moving entity.

Early glimpses of her personality show a sassy British woman who tells her creator to “piss off” (Van der Velden’s idea) and makes a stab at self awareness in the video out over the summer. “I’m Tilly Norwood, the world’s first AI actress,” she says, “or, as some might call me, the end of civilization.” 

Now, Van der Velden is hoping for a second chance with skeptics as she constructs Tilly’s personality, behavior and conversational style. (In typical showbiz fashion, Tilly’s beauty came before her brains.) Next year, she expects Tilly to be able to interact with fans directly.

Now Particle6 is working with lawyers and ethicists to put guardrails around Tilly. They need to know what she’ll say if someone professes falling in love with her, for example, or if she’s presented with an unsafe situation.

Van der Velden is experimenting with tough questions for Tilly and assessing the answers. “I want them to be witty, so that when she comes out, her responses will be social-media worthy,” she said. 

The other day, Van der Velden asked her if she had any words for Cameron, the director who pronounced himself appalled by the idea of AI actors. 

Tilly kept it short. “Oh, how cute, James,” she said, and left it at that.   

Write to Ellen Gamerman at ellen.gamerman@wsj.com