She Plays a Young Serena Williams

Name: Demi Singleton

Age: 14

Hometown: New York City

Currently Lives: In a Spanish-style house in Los Angeles with her parents and two siblings.

Claim to Fame: Ms. Singleton is an actress, singer, dancer and cellist who plays a young Serena Williams in “King Richard,” alongside Will Smith, who plays her father, Richard Williams.

She started dancing at age 3, singing at age 7 and soon booked roles on Broadway. “King Richard” is her big-screen debut. “I just felt so loved and taken care of the entire time,” she said. She developed a sisterly bond with Saniyya Sidney, who plays Venus Williams. “We were on the phone with each other all day yesterday. We’re really like siblings now.”

Big Break: Ms. Singleton started pursuing acting professionally at age 10, after seeing “Matilda” on Broadway. “I was able to see a bunch of young people doing what they love, and having so much fun on stage,” she said. “That’s what made me realize that I wanted to be an actress.”

She booked “School of Rock” on Broadway shortly after signing with her first agency, and next played Young Nala in “The Lion King.” “It was hard in some ways, but it really wasn’t like work,” she said. “Being on Broadway is just fun, you just have an enjoyable time on stage.”

Latest Project: For “King Richard,” which opened in theaters and HBO Max on Nov. 19, Ms. Singleton studied Serena Williams’s mannerisms, but nothing prepared her more than meeting the Williams sisters on set. “We had a very long conversation about their teenage dating lives,” she said. “It was really cool to get to see them from a different perspective, and see them talking about something other than what they’re famous for.”

Next Thing: Ms. Singleton is hoping to release music within the next year, which she describes as a mix of pop and R&B. “The whole message of everything that I’m releasing is equality and love and kindness,” she said, “because we’re in such a weird time right now.”

Learning Curve: Ms. Singleton had never played tennis before “King Richard.” She took three lessons before her final audition, because the casting directors wanted to see her and Ms. Sidney hit some balls together. “I was learning to play like a literal icon,” she said. “I had to mimic her. If I were to go play right now, I wouldn’t know how to play like anyone else but Serena Williams.”