John Stamos Reveals How He Tried to Defend John Travolta From Captain America Star Chris Evans

John Stamos once introduced John Travolta and Chris Evans at an Oscars' party — and then tried to ward off the Captain Americastar after he asked Travolta to record a video message for his mother.

"He whips out his phone, Chris, and says, 'Will you do a video for my mom? My mom really loves you,'" Stamos said on Jimmy Kimmel Live. "I go, 'Whoa, whoa.' I'm all of a sudden his defender, his protector."

"You were defending him from Captain America?" Kimmel asked with a laugh.

"He says, 'Well, I'll just do it fast, John, [it's] Captain America.' And then, 'Hello Captain America's mother, this is John Travolta,'" Stamos said while offering his best impression of the Grease star.

"And he talks to her for five or six minutes or something!"

Evans commemorated wrapping filming on Avengers 4 early last month with a sentimental tweet that fueled speculation the star would be exiting the role of Captain America and ending his time with the Marvel Cinematic Universe.

"It was an emotional day to say the least," Evans wrote in the Oct. 4 tweet. "Playing this role over the last 8 years has been an honor. To everyone in front of the camera, behind the camera, and in the audience, thank you for the memories! Eternally grateful."

Evans later clarified the tweet during an appearance at ACE Comic Con in Chicago, explaining the tweet wasn't a spoiler.

"I should clarify that regardless of how Avengers 4 ends, I would have tweeted the exact same thing. That last day of filming was a very emotional day and it was the culmination of almost 10 years of filming and 22 movies, this unbelievable tapestry," Evans said.

"You feel a lot more emotions than I think even I thought I'd feel. And I felt it was appropriate to share the gratitude. I know it had a ripple effect but I am neither confirming or denying anything."

Avengers 4 opens May 3.