The cast of 'Avengers: Infinity War' still don't know the title to its sequel.

Elizabeth Olsen - who plays the role of Scarlet Witch in the Marvel movies - has admitted that despite being a veteran of the franchise, she's not been told the name of the sequel, which was shot immediately after 'Infinity War' last year.

Asked whether she knew the title of the follow up, Elizabeth confessed: ''No. Someone just told us that they were going to release it after this movie.

''When are they releasing the name? I have no idea what it is. I've been calling it 'Avengers 4'.''

Elizabeth also revealed she's been sworn to secrecy regarding the film's plot.

She told Digital Spy: ''We can choose to sit in a locked private room with an iPad that has the full script - which also has a bunch of lies in it - because they won't print the full script.

''But if you don't want to do that, they give you your pages that pertain to your character, and then they orally explain to you what's happening in the rest of the movie.

''So we do know what happens as much as they have given us ... unless they're lying to us, and planting strange seeds.''

In fact, Paul Bettany - who plays The Vision in the Marvel movies - revealed the film's makers have planted some ''fake pieces'' in its script.

He explained: ''It's not quite true that we don't know the story. You read the script, there are some fake pieces.

''Sometimes you'll get there and they'll say, 'Everything you read - that doesn't happen. We're going to do this'. And then you do it. It's actually been exciting ... once you yield to it.''