“Ant-Man” Star Kathryn Newton on the Best Advice Paul Rudd Gave Her: ‘Don’t Hold Back’ (Exclusive)

‘Lisa Frankenstein’ star Kathryn Newton is recalling some of the best wisdom she’s gleaned from Paul Rudd, Reese Witherspoon and more

Kathryn Newton is recalling the best advice she’s ever received from an industry veteran and mentor.

“Paul Rudd told me not to hold back when I started Ant-Man,” says Newton, who joined the Marvel Cinematic Universe in 2023’s Ant-Man and the Wasp: Quantumania.

“I think that's just good advice for anybody with whatever you do in life, whatever your job might be,” the actress, 26, tells PEOPLE exclusively. “Put your best foot forward every day and don't hold back.”

Related: Paul Rudd Details His 'Very Restrictive' Ant-Man Diet: 'My Reward Was Sparkling Water'

It’s especially true in the world of showbiz, she adds, “because these things happen really fast.”

Newton, an avid golfer as well as actor, broke out in 2012’s Paranormal Activity 4 after appearing as a child actor on the soap opera All My Children. She's played key roles in Big Little Lies, Pokémon Detective Pikachu, The Society and now Zelda Williams and Diablo Cody’s “zom-com” Lisa Frankenstein (in theaters Friday).

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Related: 'The Society' 's Kathryn Newton Says Her Character 'Goes From Being a Little Sister to The Godfather'

Reese Witherspoon, who played her mother on the two-season run of HBO’s Big Little Lies, was another mentor and “such a brilliant actress,” says Newton. “You just have to watch her and you're reacting. And I think the dynamic with her and Jean-Marc Vallée really helped me be grounded.”

Working with filmmaker Vallée, who died in 2021, taught Newton “what it meant to be a real actor,” she adds. “I never knew where the camera was. Jean-Marc shoots 360 [degrees], so I was always just in it with Reese, and you never felt like you were on camera. It's different when you're aware of the camera, it definitely becomes a character in the scene. But in that space, it was more just really forgetting that you were shooting a show at all.”

When asked about the possibility of a Big Little Lies season 3, Newton shrugs. “People keep bringing it up to me. That's all I know!”

As for more appearances in the MCU, that’s “the most top-secret,” says the actress, who played Cassie Lang, daughter of Rudd's Scott Lang. Quantumania costarred Evangeline Lilly, Jonathan Majors, Michelle Pfeiffer and Michael Douglas.

“I wish I could tell you, but obviously everything's always a secret these days,” quips Newton with a laugh. “You just can't even mumble the word Marvel!”

Related: Zelda Williams Says It Was 'Really Daunting' to Make Her Directorial Debut Lisa Frankenstein (Exclusive)

Lisa Frankenstein also stars Cole Sprouse, Liza Soberano, Henry Eikenberry, Joe Chrest and Carla Gugino. For Newton, all her costars as well as Williams and Cody have joined her growing list of fellow artists from whom she’s learned plenty. 

“Everybody changes me,” she says when asked what she’ll take away from leading the film. “You meet one person and they change your life, even if it's a little bit. I think working with Cole and Zelda changed my life. This movie definitely has changed me.”

Lisa Frankenstein opens in theaters Friday.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.