Iron Man, Thor and Black Widow - or at least the actors that play them - were in London Thursday, April 19 as "Marvel Avengers Assemble" held its European premiere, AP reported.

Hollywood actors Robert Downey Jr., Chris Hemsworth and Scarlett Johansson, who play the heroes, were on hand at London's Vue Westfield, with Johansson saying it was nice "to actually play someone who's got a lot of conviction and who is really ready to kick some booty."

Johansson, who wore a black and scarlet floral corset, shared the red carpet with co-stars including Jeremy Renner, who plays sharp-eyed archer agent Hawkeye; Tom Hiddleston, the villain Loki; and Mark Ruffalo, who joins the superhero world as the Hulk.

Written and directed by Joss Whedon, the action adventure film follows the comic book team as they unite to fight Loki and neutralize his threat of war from another world.

The "Marvel Avengers Assemble" is being released in U.K. theaters on April 26 and in the U.S. as "The Avengers" on May 4.