Watch Jimmy Fallon's Never-Before-Seen Rejected Saturday Night Live Sketch

Jimmy Fallon is unearthing lost footage from his days on Saturday Night Live.

Joined by guest Robert Downey Jr. on his late-night talk show Wednesday, Fallon, 45, reminisced with the Dolittle star about their tenures on SNL — including some less-than-inspiring sketches.

“I was on the show for six seasons so I had so many bad ones,” said Fallon, who was a cast member on the NBC sketch comedy series from 1998-2004. Downey Jr., 54, was on from 1985-1986.

“The worst one I think, I had to find it today,” the comedian said. “Gosh, it’s so embarrassing. Plate boy and cup boy.”

Before showing the clip to viewers, Fallon explained that his inspiration for the sketch came from former cast member Horatio Sanz.

RELATED: Jimmy Fallon Reveals Which Classic SNL Sketch Almost Didn’t Make It to Air

“Horatio had all these cups and it was in rehearsal and he was shaking them back and forth and all these cups would just fly in the air like a tornado,” he recalled. “It was very odd, and so I said, ‘Let’s write a sketch, this is really funny.’ “

In the clip, host Alec Baldwin‘s character tells Fallon, who is playing a pizza restaurant employee, to give a customer a plate. As Fallon grabs a high stack of plates, he begins to lose his hold on them, and the plates wobble and fall everywhere.

In the next scene, Sanz, 50, is preparing to hand two stacks of cups to the customer when he similarly lost his handle on them, resulting in them flying all over the kitchen.

As the show cut back to Fallon and Downey Jr. in studio, the comedian joked, “I’m sweating,” while grabbing a tissue to wipe his forehead.

“The flop sweat is coming back. It was awful,” Fallon recalled.

As the two men joked about the “awful” sketch, Downey Jr. said, “Look at us here now,” earning applause from the audience.

In an episode of The Jess Cagle Interview in 2018, Fallon revealed several behind-the-scenes secrets about SNL, including that one fan-favorite sketch, Will Ferrell and Christopher Walken’s “More Cowbell,” was nearly scrapped from the show.

“It played late,” Fallon said. “Usually the weirder sketches play later on, and it almost didn’t make it to air.”

RELATED VIDEO: Jimmy Fallon Shares Behind-The-Scenes Stories Of His Most Memorable SNL Sketches

Luckily, the cowbell made the cut, and Ferrell and the rest of the cast “upped their game.”

“Will did this thing when he was playing the cowbell,” Fallon recalled. “He would play it and his shirt would come up a little bit and his gut would hang out … and that would make me laugh. On air he wore a smaller shirt.”

Fallon, who made a name for himself with his tendency to break during the funniest segments, couldn’t hold it together.

“That was my first season, and I was so out of my league with all these great comedians,” he explained. “I blew my line because I was laughing.”

The actor and comedian remembered getting scolded backstage: “They’re like, ‘No, it’s funny when you’re watching, but you can’t laugh when you’re in the sketch. You idiot. You’re acting.’ ”