The Avengers really are one big, happy family.

On The Tonight Show Starring Jimmy Fallon, the cast of Avengers: Infinity War proved they were Earth’s Mightiest Heroes by doing double duty, showing off their musical chops and explaining the origin of the Marvel Cinematic Universe.

The song began at the beginning, and in the beginning, there was Robert Downey Jr. “Here’s the story of a playboy genius who was gearing up to form some sort of crew,” he sang. Downey was joined by a former Russian spy (Scarlett Johansson), a God of Thunder (Chris Hemsworth), and one who “fought in World War II,” (Chris Evans).

In comes Chris Pratt, claiming Star-Lord as “the greatest to ever walk the Earth, by far.” Anthony Mackie and Benedict Cumberbatch sang their own introductions — a falcon and a magic doctor, respectively — while Chadwick Boseman kept it sweet and simple, singing, “Wakanda Forever.”

“So then one day all the heroes were assembled, to fight a villain who packed much more than a punch,” the cast chorused. “And this group was labeled the Avengers, that’s the way we all became the Marvel Bunch.”

The super crew got a last minute addition from the one and only Loki (Tom Hiddleston), who punctuated the song with a signature “Hello, brother,” thrown Hemsworth’s way. “Shut up!” Hemsworth pitched back from his own Brady Bunch box.

Watch the Avengers croon their new theme song above.

Avengers: Infinity War
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