Robert Downey Jr, Chris Hemsworth and other members of the Avengers superhero team have celebrated the final chapter in a 22-movie saga that ranks as the movie industry's highest-grossing franchise of all time.
At a lavish premiere in Los Angeles, hundreds of industry VIPs, cast members, fans and media watched the first showing of Avengers: Endgame, the three-hour action spectacle that has been held tightly under wraps.
The movie begins rolling out in theatres around the world on Wednesday.
Downey Jr (Iron Man), Hemsworth (Thor), Scarlett Johansson (Black Widow), Chris Evans (Captain America) and others walked a purple carpet underneath a giant, spinning Avengers logo set up inside the Los Angeles Convention Center.
A cavernous exhibit hall was turned into a movie theatre with a large screen and stadium-style seating.
Other A-list stars packed the premiere, including Chris Hemsworth's brother Liam and his wife Miley Cyrus, and Matt Damon, who had a cameo in 2017 film Thor: Ragnarok.
Endgame concludes the story of the six original Avengers in Marvel's cinematic universe - Iron Man, Captain America, Black Widow, Hawkeye, Hulk and Thor.
It picks up after last year's Avengers: Infinity War left fans hanging when many of the Marvel heroes seemed to turn to dust at the hand of the villain Thanos, played by Josh Brolin.
In Endgame, the surviving superheroes plot to kill Thanos and try to undo his damage.
The 21 previous movies from the Walt Disney Co-owned Marvel studio are the highest-grossing franchise in film history, generating more than $US18.6 billion at global box offices since 2007.
While Endgame wraps up the Avengers story, many Marvel characters will live on in future movies. Spider-Man, for example, returns to the big screen in July in Spider-Man: Far from Home.
A Black Panther sequel is also in the works.
Australian Associated Press