Olivia Wilde and fiancé Jason Sudeikis share daughter Daisy Josephine, 2 next month, and son Otis Alexander, 4

Olivia Wilde‘s kids are a little confused about their parentage — and for a hilarious reason.

The Life Itself star stopped by The Ellen DeGeneres Show Tuesday to chat with the host about her new romantic comedy and how she and fiancé Jason Sudeikis are currently handling being parents of two to daughter Daisy Josephine, 2 next month, and son Otis Alexander, 4.

One relevant topic of discussion? The huge framed art Ellen DeGeneres gave the couple as a gag gift six years ago: a photo of DeGeneres in a yellow bathing suit, which used to hang above their bed and has since led their kids to a head-scratching conclusion.

“Now it has another very special place: outside the children’s bedrooms, so it’s the first thing that they see when they wake up,” said Wilde, 34.

“Do they say, ‘Who is that lady?’ ” asks DeGeneres, 60.

“Yeah, they say, ‘Oh, that’s our real mother,’ ” the actress jokes. “And I say, ‘Yes.’ ”

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Wilde’s kids “wish they had the same room, which is very sweet” but for now sleep in separate bedrooms — and Daisy is currently trying to age herself up.

“She also lies about being 3, which is a really funny thing. You ask her, ‘How old are you?’ and she’s like, ‘I’m 3,’ ” says the mother of two. “I think she so badly wants to catch up with her brother that she’s already lying about her age.”

“She’s really very grown up; I’m amazed by her,” Wilde admits. “She’s a really funny, funny person.”

Ellen DeGeneres
Credit: Michael Rozman/Warner Bros.

Olivia Wilde and Ellen DeGeneres

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Otis is currently hugely into music, like “the Beastie Boys, which we approve of wholeheartedly,” says his mom, also recalling the Beyoncé-themed second birthday party for her son.

“He also is into, weirdly … I don’t know how he discovered it, but Ibiza-style, techno, spring-break dance-party pop,” Wilde continues, joking, “We think he might be going out at night and hittin’ the ‘clurb.’ ”

“This is why you shouldn’t send them to school — they come back with bad taste in music,” she kids. “We had done so well.”

Life Itself opens in theaters nationwide Friday.