The Barbie Moment That Caused Greta Gerwig To Fall Over Laughing

If you've seen "Barbie," you know that it's a smart, deeply emotional, and cleverly crafted film — and it's also really, really funny. Whether Barbie (Margot Robbie) is crying about how she can't be called a fascist because she "doesn't control the railways or the flow of commerce" or Ken (Ryan Gosling) is admitting that he lost interest in the concept of patriarchy when he realized how little it has to do with horses, the movie is chock full of truly funny moments, and one of the funniest had Greta Gerwig literally rolling on the floor laughing during filming.

In the beginning of the movie, Ken, trying to impress Barbie, takes a flying leap towards the plastic ocean in Barbie Land, only to smack directly into the "waves." As he flies through the air, Allan (Michael Cera), Ken's very best friend, screams in a huge, exaggerated way — and in a behind-the-scenes video featured on Entertainment Tonight, you can see Gerwig flat-out fall out of her director's chair watching Cera perform the moment. The bit is just as funny in the finished product, and obviously, it was a blast to film for Gerwig, Cera, and everybody else involved.

It might feel impossible that anybody but Michael Cera could have played the milquetoast, unassuming Allan — though Jonathan Groff was also up for the role — but he told GQ in a recent career retrospective that he almost missed out on the role due to a miscommunication with his agent.

"It was a kind of very last-minute casting," Cera said in the video. "My manager got a call checking on my availability for it, and he called me and he said, 'I got a call about this movie. It's the Barbie movie. Greta Gerwig's directing it, and it's filming in London for four months or something, so I told them you probably wouldn't want to do it because you probably don't want to go to London.'"

Cera was, understandably, baffled by this move, and asked his manager to redirect right away: "I was like, 'What! What do you mean? Call them back!' He didn't like blow it or anything, but he's like, 'I managed their expectations that you might not want to do it.' I was like, 'How can I not do it? I need to do it!'" After getting Gerwig's email, Cera said he just hung out on Zoom for as long as he had to in order to talk to her. "And she was like, 'Let's get on a Zoom right now. Here's a Zoom link, I'll be on there for the next hour,'" Cera remembered. "So she was just hanging out on the Zoom, she's just like, 'Just click that link whenever you're ready.' And then we talked about it, and it just all happened really fast from there."

So who exactly is Allan? Well, the doll he's based on a doll released in 1964 who was marketed as "Ken's buddy," a line Allan himself references in the movie when he tells a bunch of construction workers that he "fits into all of Ken's clothes." (He does this right before beating the absolute snot out of said Construction Kens.) He was retired after a pretty short period of time and replaced with a cooler "Alan" who was paired with Mitch, but the version Michael Cera plays is the original — and he's precisely perfect for the role. Cera clearly understands the character; as he told ET in the same video, "Allan is sort of like a person who doesn't belong to a group. He's sort of a loner, in a way." He's right; in a world full of Barbies and Kens, there's only one Allan, something that baffles him a bit. He does tell Gloria (America Ferrera) and Sasha (Ariana Greenblatt), though, that Allans escape Barbie Land all the time — N*SYNC is, according to him, made up entirely of Allans. 

Cera also told ET that the experience of making "Barbie" was pretty amazing thanks to Greta Gerwig herself. "I can't imagine anybody else directing it other than Greta," he said. "She's been so amazing with so many elements and this enormous production design, so many moving pieces — and in the midst of all that, she's so free and inventive and changing things. That's a very infectious spirit, too, that the cast can really pick up on and feel like we can play and have fun."

"Barbie" is available to rent or buy on demand now, and it will return to theaters in IMAX later this month.