'SNL' shows behind-the-scenes footage of 'Beavis and Butt-Head' skit that broke Heidi Gardner

"Saturday Night Live" star Heidi Gardner made headlines this week after video of her breaking character in a big way on the show's April 13 episode went viral.

Gardner began laughing uncontrollably during a nutty sketch about AI technology when she turned around to find castmate Mikey Day dressed as Butt-Head from the 1990s cartoon "Beavis and Butt-head."

Now, thanks to a video "SNL" posted April 18 on Instagram, fans can see that Gardner, who rarely breaks character on the live comedy show, struggled to look at Day as Butt-Head even in the show's run-thru and dress rehearsal.

The new video is divided into two parts: On the bottom it shows Day sitting in a chair as the show's makeup artists transform him into Butt-Head, scary gums and all.

On the top, viewers can watch as Gardner, who plays the moderator of a NewsNation show in the sketch, and her castmates, including Kenan Thompson, who plays an MIT professor who's an expert on AI, first read the sketch with their scripts in front of them at a table.

Next, we see the run-thru using furniture and props on the show's set. Day wears a Butt-Head wig and just a touch of makeup, which makes Gardner giggle a bit.

Later, at the dress rehearsal, Day shows up wearing more makeup — thus looking even more like Butt-Head — and Gardner briefly struggles with her laughter.

By the time of the live show, Day is practically channeling Butt-Head and Gardner loses it the moment she sees him, pausing for nearly half a minute as she cracks up laughing.

The wacky live sketch kicked off with Thompson's professor character becoming distracted by a man in the talk show's audience — played by the show's guest host, Ryan Gosling —  because his blond pompadour and his nose makes him look just like Beavis.

“There’s a gentleman in your audience who looks strikingly similar to Beavis from the cartoon 'Beavis and Butt-Head,'” Thompson tells Gardner.

Gardner pleads ignorance by saying she doesn’t know the cartoon, while Gosling appears surprised there’s any sort of controversy and agrees to move when asked.

Gardner and Thompson continue their AI discussion, but it’s a short-lived talk because Thompson is once again thrown off when he discovers the man who replaced Gosling's Beavis in the audience looks exactly like Butt-Head.

Gardner, growing impatient, asks if Thompson would like the second man to move. When he says yes, Gardner looks back at Day for the first time to tell him to switch seats, and she totally loses it.

Beavis and Butt-head (YouTube)
Beavis and Butt-head (YouTube)

“Sir,” she says before she busts out laughing for about 20 seconds while the audience cheers.

When Day realizes Gardner's talking to him, she continues to laugh, even as she tries to soldier on.

A few moments later, an audience member stands to ask a question, but is overshadowed because she’s standing behind Beavis and Butt-Head.

Beavis and Butt-head (Shutterstock, YouTube)
Beavis and Butt-head (Shutterstock, YouTube)

“Look, they’re even sitting like they do on the show!” an incredulous Thompson exclaims, while Gosling laughs and struggles to spit out his lines. Perhaps what’s most impressive is the fact the extras in the sketch remain stone-faced.

“This is honestly the first time I’ve ever heard that I look like this Butt-Head person,” Day says.

“For those just tuning in, this is NewsNation, not the Cartoon Network,” Gardner says, prompting Day and Gosling to laugh exactly like Beavis and Butt-Head before they reveal they’ve never even met.

Saturday Night Live - Season 49 (Will Heath / NBC)
Saturday Night Live - Season 49 (Will Heath / NBC)

The sketch draws to a close when Gardner says they’ll soon be joined by men from Texas who lost their jobs to AI. A cutaway then shows the men are real-life versions of characters from “King of the Hill,” another show created by Mike Judge, who also brought “Beavis and Butt-Head” to life.

Gardner discussed the sketch, including the studio audience's reaction to her bursts of giggles, in an April 15 interview with Vulture, saying, “I had coached myself for so many years to not break. Being a perpetual people-pleaser rule follower, it was nice that I broke the rules — unintentionally, of course. I can’t help what I saw, but people were okay with it. Not only okay with it but encouraged it. That’s all the feedback I’ve gotten since.

“I left the stage a little bit in shock,” she continued. “Then the anxiety set in and I was like, Oh my God, was that okay? I had some friends in my dressing room, and they were like, 'Of course, it was okay.' So many other writers and cast members came up and said, 'Good job.' I’m like, What? I actually didn’t do my job.

This article was originally published on TODAY.com