San Diego, California - Oscar-winner Robert Downey Jr. announced his return to the Marvel superhero films during a blockbuster Disney presentation at Comic-Con Saturday, as the company attempts to reinvigorate its all-time record-grossing movie franchise.

Harrison Ford and Pedro Pascal were also officially unveiled among a batch of new stars joining the movie franchise, which has grossed an unprecedented $30 billion at the box office but, in recent years, has suffered a number of high-profile flops.

Marvel film president Kevin Feige unveiled new details about multiple upcoming superhero movies in front of a crowd of screaming devotees at the San Diego, California gathering on Saturday – but nobody drew a louder reaction than the returning Downey Jr.

The actor, who launched the entire Marvel movie universe with 2008's Iron Man, will return as a totally different character – Doctor Doom, a prominent villain in the Marvel comic books – it was revealed.

Joke of the Day Joke of the Night for December 19, 2024: The best Christmas jokes to laugh the day away

He appeared anonymously on stage among a group of hooded and masked figures, before stepping forward and revealing his much-rumored return.

"New mask. Same task. What'd I tell you? I like playing complicated characters," said Downey Jr., to the delight of the assembled Marvel obsessives.

Downey Jr. won an Oscar this year for his role in Christopher Nolan's Oppenheimer, and had seemingly retired from the Marvel films in 2019.

The presentation was the hottest ticket of the four-day pop culture extravaganza, with fans lining up for hours to get a coveted seat.

Marvel fans have complained in recent years about over-complicated plotlines and the departure of beloved characters, including Downey Jr.'s Iron Man, with some calling for a wholesale reboot of the movies.

The franchise was also rocked by domestic violence revelations about actor Jonathan Majors, who had been set to become the major new supervillain across multiple films.

Majors, who was convicted of assaulting and harassing his then-girlfriend, was dropped by Marvel.

Joke of the Day Joke of the Night for December 20, 2024: The best winter jokes to laugh the day away

The answer to who will fill that role was seemingly answered by Downey Jr.'s return as a villain.

Joe and Anthony Russo – the brothers who previously oversaw 2019's Avengers: Endgame, which briefly became the highest-grossing film of all time at more than $2.79 billion – will also return.

They will direct Avengers: Doomsday in May 2026 and Avengers: Secret Wars in May 2027.

The Marvel event opened with dozens of singers and dancers dressed in the red and yellow of Deadpool & Wolverine, the new R-rated superhero movie that is enjoying a record-breaking opening this weekend.

"But Hall H doesn't just look back... Hall H looks forward," said Feige, referring to the Comic-Con event's famous venue, before setting out Marvel's plans for the next three years.

Next year will see three films including February's Captain America: Brave New World, with Harrison Ford as Thaddeus Ross, a US president who turns into a Red Hulk.

"I wanted a piece of the action," said Ford on joining the Marvel franchise.

Also due in 2025 are Thunderbolts in May, starring Florence Pugh, and July's The Fantastic 4: First Steps, starring Pedro Pascal and set in 1960s New York.

Earlier on Saturday at Comic-Con, Disney's rival studio Warner, which runs the DC superhero movies, offered a glimpse at The Penguin, starring Colin Farrell.

Spun off from the 2022 film The Batman, which starred Robert Pattinson as a grungy, noirish incarnation of the beloved superhero, The Penguin will hit HBO on September 19.