Blake Lively Says Her Kids Know She and Ryan Reynolds Are 'Actors' but Don't Know What It Means

Blake Lively‘s kids are in the know when it comes to Mom and Dad’s careers — kind of.

The actress, 32, and husband Ryan Reynolds are well-known Hollywood actors, and as Lively revealed to PEOPLE on Monday night at the New York City premiere of her new drama The Rhythm Section, their two older daughters are just starting to catch on.

“They know that we’re actors, they just don’t know what that entails,” Lively says of 3-year-old Inez and her big sister James, who turned 5 last month. (Reynolds, 43, confirmed the arrival of the couple’s third daughter in October.)

In The Rhythm Section, Lively stars alongside Jude Law and Sterling K. Brown as a woman heading down a violent path of revenge after her family is killed in a mysterious plane crash. Directed by The Handmaid’s Tale‘s Reed Morano, the film is a modern adaptation of the first of British thriller writer Mark Burnell’s Stephanie Patrick series.

“Can you imagine if my daughter knew what I went through in this movie? I mean, they would be terrified!” the actress told PEOPLE, laughing. “She’d either be terrified for me or of me, neither of which is something that I want her to feel.”

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Lively stepped out for the New York City premiere of her new film on Monday alongside her mom Elaine and sister Robyn. For the evening, the Gossip Girl alumna went classically chic, wearing a long black off-the-shoulder velvet gown by Dolce & Gabbana with a plunging neckline.

She accessorized the look with black leather opera gloves and over-the-knee Christian Louboutin boots with button detail, adding a touch of sparkle with an impressive Lorraine Schwartz necklace made with South Sea pearls, diamond chains and a 50-carat Colombian emerald.

While each accessory added to the star’s statement look, Lively revealed her ultimate secret to looking glamorous on the red carpet was out of sight.

“Corsets make you feel like you’re on the brink of having it together,” she told PEOPLE, before jokingly adding, “But, you know, this is not real life. I gotta get this thing off!”

RELATED VIDEO: Blake Lively Wears a Corset on First Red Carpet Post Baby No. 3: “I Gotta Get This Thing Off”

On Tuesday morning, the A Simple Favor actress stopped by Good Morning America to chat about her new movie and revealed that since she and her husband welcomed their third daughter late last year, activity at home has sped up considerably.

After co-host Michael Strahan asked her what it was like going from two to three children, Lively quipped, “It’s like going from two to 3,000. [We] have so many children. It’s pretty [crazy]. We’re outnumbered. It’s a lot.”

“People say that from two to three, it’s the same, it’s kind of easy. Those people do not have three kids,” the star joked. “It is crazy. But I’m here!”

The Rhythm Section opens in theaters Friday.

For more from Blake Lively, pick up the latest issue of PEOPLE, on newsstands Friday.