Lisa Kudrow's son used to call Jennifer Aniston "Mommy"

Appearing on 'Conan', host Conan O'Brien said: "He got a little confused. I know that he really was obsessed with Jen."

Lisa - who was pregnant during the fourth season of the show -

confirmed: "He'd fly into her lap. Well, she's a love bug, and that made sense. And I was always glad for anyone that Julien felt love for and felt from."

"But then at home, she'd be on TV, and he'd go, 'Mommy!'"

The actress - who is married to Michel Stern - revealed Julian has seen episodes of the show in recent years so he could talk to his friends about it, and she joked he was more impressed by everyone else's performances than her own portrayal of Phoebe Buffay.

She said: "I know he hasn't seen every episode. I know for a while, in school, people were watching it. And he kind of felt like he had to, so that he can participate in what everyone else was watching. And he did really think that everybody else was very funny on the show."

Jennifer was among the stars to wish Julian a Happy Birthday when her friend and former co-star shared some photos of him on Instagram to mark the occasion earlier this month.

The 'Morning Show' star commented on the 7 May post: "Happy Birthday, Juls!!! Feels like yesterday that you arrived.(sic)"

The 'Easy A' actress recently admitted she'd got "more sensitive" when she had her son and stopped finding things as funny as she used to.

She said: “When I became a mother, everything changed. The instant my son arrived, I thought, 'Oh, OK, now I get it. Nothing else is ever going to be as important as this.'

“And my outlook on life changed too - one thing that's kind of sad is that a lot of things that I had found funny before just stopped being funny to me then, and there were a lot of things on TV and in the movies that I couldn't watch anymore.

"Any sort of doctor shows with kids ending up in the emergency room, anything that involved children getting hurt. Before, I'd been able to see movies such as 'Sophie's Choice' and 'Schindler's List' - I couldn't even begin to watch them now. I guess I got sensitive!"