Thirty-somethings playing teenagers is a story as old as time in Hollywood.

Shirley Henderson, who played Moaning Myrtle in the “Harry Potter” franchise, talked about how old she was when she took on the role, which required a teenager.

She was 37 years old at the time and represented a 14-year-old schoolgirl.

Shirley Henderson on the set of the movie
Shirley Henderson on the set of the film “Harry Potter and the Goblet of Fire” in 2004.

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“The casting director said, ‘Do it, and don’t mention your age,’” Henderson recalled in an interview with The Independent, published last week.

She evoked a “little moan,” which her character asks for, and also dressed the part.

“I went to the audition dressed like a schoolgirl (white shirt, black skirt, ponytail) thinking, ‘This is ridiculous,’” Henderson, now 60, said in an interview with Radio Times earlier this month.

“I did my little bit for them and they thanked me. Months went by and I thought that was it, but then they called my agent, asked to see me again and offered me the role,” he said.

“Myrtle is an older person in a young person’s body, and because she’s ghostly, there’s a kind of haze,” the actor shared. “You’re not looking too closely at my face so we can get our way.”

Shirley Henderson attends the
Shirley Henderson attends the ‘I Swear’ London Gala Screening on September 29 in London.

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Actors, mainly women, being asked to hide their age is nothing new.

“Derry Girls” and “Bridgerton” star Nicole Coughlan has previously spoken out about being asked to hide her age at auditions because she looks many decades younger than her 38 years.

“I mean, it’s kind of strange, because many, many years ago, people in the industry had advised me to lie about my age,” Coughlan said in an interview with Refinery29 last year. “I didn’t really feel comfortable with that, mainly because I think I’m not a good liar. And I would feel weird about that.”

Coughlan, 38, has spoken before about being asked to hide her age.
Coughlan, 38, has spoken before about being asked to hide her age.

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Coughlan said he usually says his age, which is “kind of hard, because the industry is ageist.”

“There are times when I come home and think: Should I not have revealed it? Shouldn’t I have done it?” he wondered.