Mark Ruffalo doesn't just fight to protect Earth on the big screen as Avengers member Bruce Banner. The actor also spends much of his time advocating for environmental causes like Water Defense, the nonprofit organization he co-founded. Now the actor has teamed up with GoRaff to raise money for the clean water initiative and give a lucky winner a truly mighty experience with the big screen Avengers.

The winner of the raffle, along with a friend, will be flown to the London premiere of Avengers: Age of Ultron, where they'll meet Ruffalo and other members of the cast. The charity, as Ruffalo describes in the GoRaff video, is "dedicated to bringing you clean, fresh drinking water and fighting the people who pollute our water."

Related: Donate to Charity For a Chance to Party With Robert Downey Jr.

The purchase of raffle tickets also gets fans various prizes; $25 gets you five raffle tickets and an "exclusive video message" while $500 gets you 100 tickets and a Hulk action figure autographed by Ruffalo. For more information, check out GoRaff and watch the video below.

You could join me at the @Avengers: Age of Ultron premiere! Interested? http://t.co/PqAeNDYIUf https://t.co/0p98QV5Jd4

— Mark Ruffalo (@MarkRuffalo) March 16, 2015