Avengers: Infinity War has made its theater rounds, but even the most dedicated fans haven’t spotted all of its surprises. In fact, it looks like a special cameo was only just spotted, and it involves someone Thor fans know already.

Recently, Avengers: Infinity War hit Digital HD, and the movie's special features host plenty of never-before-heard details. If you check out the commentary track, then fans will hear all about Kenneth Branagh’s cameo in the film.

As it turns out, the director of Thor lent his voice to the Avengers flick at the very beginning. When the feature opens, fans hear an Asgardian sending out a distress signal after Thanos’ ship launches an attack on Thor. The line is the first one featured in Avengers: Infinity War, and it was Branagh who recorded it.

“This was an amazing surprise, by the way. We had this idea very late in editorial, to ask the amazing Sir Kenneth Branagh to come in and do the opening distress call over the logo that sets the stage and carries us into the scene with Thor and Thanos and Loki on the arc,” director Joe Russo says in the commentary.

Stephen McFeely pipes in about the little-known cameo as well. The screenwriter said the dialogue was well-planned as the distress call helped set up the film’s dire stakes even before it really began.

“This is a movie that starts in medias res, right? It’s so packed and jam-packed with stuff, that you even have to use the opening credits to tell a story,” McFeely said.

Of course, Branagh isn’t the only cameo hiding inside of Avengers: Infinity War. There is the usual Stan Lee cameo as the comics creator is seen driving a school bus, but that isn’t all. Originally, the film featured a special cameo of Happy Hogan played by Jon Favreau. Tony Stark’s uber-loyal bodyguard shows up while the superhero visits the park with his fiance Pepper Potts, but the scene was ultimately cut before Avengers: Infinity War could hit theaters.

Did you notice this sneaky little cameo? Let me know in the comments or hit me up on Twitter @MeganPetersCB to talk all things comics and anime!