Jason Kelce Autograph Seeker Goes Berserk On Ex-NFLer, 'You P***y, F*** You!'

A man seeking a Jason Kelce autograph on Thursday night went ballistic on the former NFL star ... calling him a "p***y" and screaming out "f*** you" repeatedly, but Travis Kelce's big bro admirably deescalated the situation -- and the tense moments were all captured on video by TMZ Sports.

The wild scene played out just a couple hours ago in Hollywood ... as Jason was leaving an appearance on "Jimmy Kimmel Live!"

Several autograph seekers had camped outside of the studio in an effort to snag the former Philadelphia Eagles player's John Hancock as he departed ... but when Jason bypassed them all and headed for his car -- one of the signature hunters snapped.

Check out the vid -- the guy went nuclear ... accusing Jason of big-timing them -- while yelling obscenities over and over again.

"You ain't nobody special!" the man hollered as Jason got into his ride. "You're some s*** bag, f***ing guy that thinks he's on some pedestal!"

The shouting was so relentless, Jason actually got out of his car to try to explain himself.

"I have a habit of not signing for people that follow where I'm going," he stated.

The man, though, didn't let up -- and at one point he appeared to challenge Jason to a fight.

"I'll be running the Marvel Cinematic Universe," the guy said. "Watch for me, you p***y! F*** you. And f*** your love!"

But seconds later, Jason managed to calm the situation down -- by heading over to the autograph seekers and promising to sign their things.

As Jason put pen to everyone's paper -- the man's attitude changed ... and he apologized.

Eventually, Jason signed for the guy -- and shook his hand. As the future Hall of Famer walked away, the man said he was sorry again.

"You're good, bro," Jason told him.

It's all, of course, a stark contrast to Nov. 2 -- the last time Jason was seen being heckled while out in public.

You'll recall, during that incident outside of the Penn State vs. Ohio State game, Jason smashed an agitator's phone after the man was heard calling Travis an anti-gay slur.

Jason expressed remorse over the encounter in the days after -- and he vowed to make better decisions moving forward.