John Mulaney didn't meet Olivia Munn's mother until after their first child had been born

Olivia told 'Late Night With Seth Meyers': "So Malcolm was born the day before Thanksgiving and my mom comes, first of all, never met John by this point."

Her mother didn't "even say 'hi' to John" at first, instead removing frozen turkeys from her luggage as she revealed a family "tradition" to the 'Saturday Night Live' star.

Olivia - who gave birth to baby girl Méi June in September last year - recalled: "She says to John, 'You know, it's so exciting, in my family with all of our kids, the tradition [is] we put a drumstick in their hand for their first Thanksgiving when they're a baby'...

"I was like, 'That's not a tradition. What is she talking about?' "

John thought the tradition was "cool", but Olivia was totally baffled by her mother insisted it happened for "everybody's first Thanksgiving".

She phoned her siblings to see if they had any photos to back their mother up.

She added: "They said, 'No because she's lying. That's not true.' "

However, they still took the photo, and her mother made sure to get the last laugh.

Revealing the snap on the late night talk show, she said: "So, in this photo, John's holding Malcolm. My mom gets her turkey leg, she puts it there, she pats his hand and goes, 'Okay a new tradition.' "

John - who revealed last summer he had secretly tied the knot with actress Olivia in New York City - previously opened up about his new in-laws, including Kim, who immigrated from Vietnam to the US in 1975.

Asked about getting to know his wife's family, he told 'Late Night with Seth Myers': "It's the greatest single time in my life.

"I've been in a lot of interesting situations. I've never - marrying into a large Vietnamese family is one of the most fun things I've ever done."

When his friend asked for more details, John quipped: "If I did a perfectly accurate impersonation of my mother-in-law, it would be a career ender."