Elizabeth Olsen has finally confirmed months of rumour and speculation by stating that she has joined the cast of The Avengers: Age of Ultron.

Samuel L Jackson (who plays Nick Fury) had mentioned Olsen's role in a recent interview with The Wall Street Journal, and now the actress has confirmed to MTV News that she will play Scarlet Witch, Magneto's daughter.

The Avengers: Age of Ultron will also introduce Scarlet's twin brother, Quicksilver, played by Olsen's Godzilla co-star Aaron Taylor-Johnson. "We get to play husband and wife, and we get to play twin brother and sister," she said.

"It's also fun because even though in Godzilla we play husband and wife, we don't have a lot of scenes together. I just love him. I love his family. I love his kids. I'm so excited . . . to actually work with each other. I think it's going to be fun."

Olsen was also fulsome in her praise for Avengers' director Joss Whedon. "He's very smart. He's too smart. He might be too smart," she said. "Some people are too smart for their own good, but he's amazing."

The Avengers: Age of Ultron is due for release in May 2015.