It's not very often that we see Marvel heroes fight with each other, especially when it's outside of the screen.

But because Seattle Seahawks has made it to Super Bowl 2015, "Captain America" star Chris Evans, who's rooting for New England Patriots, decided to tease his Marvel co-superhero "Guardians of the Galaxy" lead cast Chris Pratt.

"Well, well, well @prattprattpratt, looks like our teams are going into battle," Evans tweeted following the win of Seahawks to enter the Super Bowl 2015 "For the next 2 weeks, you are not my friend, you are my enemy," Evans posted.

Almost immediately, Pratt fired back at Evans expressing his support for his team through Twitter.

"We both know there's only one Captain America and his name is Russell Wilson," Pratt tweeted, adding the hashtags "SuperBowlBound" and "Repeat."

And so, Evans, who grew up in Boston, decided to challenge Pratt, who on the other hand spent his childhood in Washington.

"Them's fighin' words. Stakes?" Evans replied to Pratt's tweet, adding "#whatisaseahawkanyway #somethingtombradyhunts."

Thus, "Guardians of the Galaxy" star Chris Pratt challenged "Captain America" star Chris Evans in a bet for charity.

"OK. Seahawks win you fly yourself to Seattle, visit @seattlechildren hospital as Captain America, waving the 12th man flag," Pratt tweeted.

Evans then accepted stating his bet as well.

"I accept. And when the Patriots humiliate your seachickens, I expect Star-Lord to arrive at @chris_haven in a Brady jersey," he tweeted.

Who are you rooting for in the biggest Marvel duel as of date? "Captain America" star Chris Evans of "Guardians of the Galaxy" lead cast Chris Pratt? Seahawks or Patriots? Sound off in the comments below.