A new trailer for "Avengers: Doomsday," the 39th film in the Marvel Cinematic Universe, premiered Friday at the D23 Disney Entertainment Showcase. Marvel Studios president Kevin Feige introduced the trailer, joined by actors Robert Downey Jr., Chris Evans, and Hayley Atwell.

The trailer centers on the supervillain Victor von Doom, also known as Doctor Doom, who is portrayed by Downey Jr. According to Marvel, the film's plot involves heroes from three different universes on a collision course with an existential threat.

In addition to Downey Jr., Evans, and Atwell, the ensemble cast includes Chris Hemsworth, Pedro Pascal, Paul Rudd, Anthony Mackie, Florence Pugh, Vanessa Kirby, Ebon Moss-Bachrach, Wyatt Russell, Channing Tatum, Ian McKellen, Patrick Stewart, Joseph Quinn, Sebastian Stan, Kathryn Newton, Alan Cumming, and Tom Hiddleston.

"Avengers: Doomsday" is scheduled for release on December 18, and tickets are now available for purchase.

D23, billed as The Ultimate Disney Fan Event, is a biennial exposition where Disney previews upcoming projects and honors its history. This year's event is taking place at the Anaheim Convention Center through Sunday.

The Walt Disney Co. is the parent company of Marvel Entertainment and ABC News.