Chris Evan & Chris Pratt -- Superheroes Make Super Bowl Bet

Super Bowl XLIX isn't just the Seahawks vs. the Patriots ... it's Captain America vs Star-Lord ... because Chris Evans and Chris Pratt just laid down an EPIC bet on the big game in Arizona.

It all started Monday, the day after Evans' Patriots clinched a spot in the Super Bowl by deflating the Colts 45-7. He took to twitter to remind his fellow Marvel Super Hero that for the next two weeks they ain't buds.

"Well, well, well @prattprattpratt, looks like our teams are going into battle. For the next 2 weeks, you are not my friend, you are my enemy."

That's when Pratt -- a huge Seahawks fan -- laid down the gauntlet, proposing a bet whereby if the the Seahawks win, Evans has to fly to Seattle and visit a local children's hospital in full Captain America regalia, waving the 12th Man flag.

Well, Captain America never backs down from a fight ... and fired back, saying that if the Patriots win Star-Lord has to show up at his non-profit housing venture "Christopher's Haven," in a Tom Brady jersey.

C'mon ... this is pretty awesome.