Robert Downey Jr. is about to make a seismic return to the Marvel Cinematic Universe, but this time he's trading the Iron Man suit for a green cloak and a grudge. In Avengers: Doomsday, hitting theaters December 18, 2026, Downey Jr. will play the iconic villain Doctor Doom, joining a star-studded ensemble that includes Chris Hemsworth, Anthony Mackie, Tom Hiddleston, Florence Pugh, Vanessa Kirby, Pedro Pascal, and many more. It's the biggest Marvel event since Endgame, and fans are already buzzing about how the Russo brothers will handle bringing back an actor so deeply tied to another character.
In the meantime, audiences are revisiting one of Downey Jr.'s most audacious performances. Tropic Thunder, the 2008 action-comedy from Ben Stiller, has suddenly become a streaming sensation on Paramount+. As of this week, it ranks among the platform's top ten most-watched movies in the U.S., trailing only blockbusters like Top Gun: Maverick. The film's resurgence is a clear sign that viewers are hungry for Downey Jr.'s brand of fearless, over-the-top entertainment ahead of his MCU comeback.
The movie itself is a satirical masterpiece that skewers Hollywood ego and war-film clichés. Downey Jr. plays Kirk Lazarus, a method actor who undergoes a controversial pigmentation procedure to portray a Black soldier—a role that sparked debate then and now, but is widely regarded as a comedic tour de force. The cast is a who's-who of comedy royalty: Ben Stiller, Jack Black, Matthew McConaughey, Danny McBride, Nick Nolte, Jay Baruchel, and Steve Coogan all deliver memorable turns. Even Tom Cruise pops up in a nearly unrecognizable cameo as the foul-mouthed studio exec Les Grossman, a performance that has long fueled rumors of a spin-off.
Speaking of that spin-off, co-writer and star Justin Theroux recently gave fans a glimmer of hope. In an interview, Theroux confirmed that a Les Grossman project has been "kicked around in theory and in reality," with "a couple of attempts at points of entry." He added, "I think we all look forward to hopefully making that happen," though he cautioned, "There's no start date or anything." So while a Grossman spin-off isn't imminent, the idea is very much alive.
Tropic Thunder may have had a modest theatrical run—earning $191 million against a $90 million budget—but its legacy has only grown. It's now considered a modern comedy classic, and its streaming success proves that audiences still have an appetite for its sharp, unapologetic humor. For those who haven't seen it, or want to relive the chaos, it's the perfect warm-up for Downey Jr.'s villainous turn in Doomsday.
This isn't the only classic finding new life on streaming this month. Disaster movies are also dominating May 2026, with 'The Day After Tomorrow' climbing the charts as audiences crave apocalyptic thrills. Meanwhile, 'The Nowhere Man' has become Starz's sleeper action hit, proving that streaming is the new home for genre gems.
As the countdown to Avengers: Doomsday continues, expect more Downey Jr. deep cuts to surface. For now, Tropic Thunder is the must-watch rewind—a reminder that before he saved the universe, he was willing to lampoon it.
