'Avengers: Age of Ultron': Secret roles for Julie Delpy and Linda Cardellini | EW.com 

still has some surprises to reveal. Now we have learned that Julie Delpy and Linda Cardellini will appear in the film in roles that are being kept hush-hush.

The news was revealed when the two were included in the cast list attending the April 13 premiere of the film in Los Angeles. Sources at Marvel Studios confirm that wasn’t a mistake, although they aren’t yet confirming who the pair will play.

Writer-director Joss Whedon has already hinted that there will be surprise appearances in the film, although EW’s sources Delpy and Cardellini won’t be playing major superheroes from the comic book universe. Instead, they will be small but meaningful supporting characters.

The casual revelation is in line with the way Marvel quietly revealed Anthony Mackie would be reprising his role as Falcon – by including his name in the credits on the official poster.

This is pure supposition, but my guess is Delpy, best known for the

trilogy, will turn up as Black Widow’s instructor, glimpsed at the 40-second mark in the second Age of Ultron trailer. In that footage, we see a woman’s hand grab a young-looking Scarlett Johansson’s face and slam her back onto a gurney.  We know Widow was trained as an assassin in the Soviet Union as a young girl, so my prediction is we’ll see Delpy appear in one of these flashback sequences.

,  is a little trickier to place. Despite the rumors, I don’t think Captain Marvel will make an appearance in

, so count her out for that. Elizabeth Olsen’s Scarlet Witch can get inside people’s heads and bring forth places and people from the past, so Cardellini could be playing almost anyone from our heroes’ history.

We have two actors, Dominic Cooper and John Slattery, playing Tony Stark’s entrepreneur father, Howard, at different points in his life. Wouldn’t it be interesting if Cardellini introduced us to the woman who gave birth to Iron Man?

But, like I said, it’s all a guessing game for now. Add your own thoughts to the comments, and also – do you really want to know beforehand, or do you prefer the movie maintain some secrets for its May 1 debut?

\'Avengers: Age of Ultron\': Secret roles for Julie Delpy and Linda Cardellini

\'The Americans\' bosses on Paige, her future, and the endgame after (spoiler!)

Casting Net: Anna Kendrick joins Zac Efron in \'Mike and Dave Need Wedding Dates\'

Will Ferrell, Kristen Wiig in Lifetime movie (no, really!)

Kendrick Lamar goes back to Compton for \'King Kunta\' video: Watch

Katie Couric pulls off \'an amazing prank\' on James Corden for April Fools\' Day: Watch

From People: Courteney Cox steals Erin Foster\'s socks in \'Barely Famous\' clip

\'Selena\' and more great movies inspired by musical lives

Drake, Anna & Elizabeth, Matt Bomer and More!