Elizabeth Olsen: Acting's just pretend

Elizabeth Olsen doesn't think it's weird going from playing Aaron Taylor-Johnson's wife to portraying his sister.

The two actors appeared alongside each other for the first time in last year's Godzilla, playing a couple. Now they are teaming up for Avengers: Age of Ultron, in which Elizabeth takes on the role of Wanda Maximoff / Scarlet Witch, while Aaron plays her sibling Pietro Maximoff / Quicksilver.

"No, because you never actually are husband and wife with someone you're working with," she reasoned to Empire when asked if the transition felt strange.

"You're just friends. You never have a relationship with them."

Elizabeth, 25, refers to 24-year-old Aaron as her "buddy" and says it helped they had some rapport before jumping into playing inseparable twins.

Appearing in a cult comic classic like the Avengers can be daunting for stars, as the franchise comes with such a large fan base. Elizabeth's Scarlet Witch has super powers she's still exploring in Ultron, including having visions and manipulating objects.

However, she's not a mutant - which Elizabeth had to learn the hard way.

"She's not a mutant," she laughed. "I almost screwed that one up at Comic-Con. I almost said 'mutated' and everyone was, 'Oooooh!' It was the worst thing ever."

The latest Avengers instalment is currently in post-production and has a release date of May this year. Also joining Elizabeth and Aaron are Scarlett Johansson as Natasha Romanoff / Black Widow, Chris Hemsworth as Thor and Robert Downey Jr. as Tony Stark / Iron Man.