As you might guess, it's a late-night show hosted by Fallon.
He used to be a singer and actor and became a talk show host in 2009. Thanks to the show's approachable theme and his unique style of hosting, the show quickly became popular.
Since he's a bit overweight, the audience affectionately calls him "Fallon the Fat."
So, whether for promotion or to boost personal influence, many celebrities and artists make appearances on "The Late Late Show."
For instance, Swift was once on the show and delivered the memorable "Living off a Banana" moment.
And recently, to promote her new movie "Hitchcock," Scarlett joined Fallon on the show.
But because Scarlett's image as "Black Widow" is so iconic, and given that the Avengers was just released this year, it was inevitable that the discussion would turn to Avengers-related topics.
