Avengers Assemble at 'Age of Ultron' World Premiere

Chris Hemsworth Avengers Premiere
Robert Downey Jr., Chris Hemsworth, Chris Evans, Scarlett Johansson and Mark Ruffalo were among the stars walking the red carpet at the Dolby Theatre on Monday.

It was a lively reunion when the stars of The Avengers assembled in Los Angeles for the world premiere of the movie's action-packed sequel, Age of Ultron, on Monday night.

Stars of the Marvel and Disney film — including Robert Downey Jr., Chris Hemsworth, Chris Evans, Scarlett Johansson and Mark Ruffalo — joined director Joss Whedon on the red carpet at the Dolby Theatre before heading inside for the star-studded event.

The actors were joined by hundreds of screaming fans who lined Hollywood Boulevard and weaved up the red carpet all the way to the theater doors.

"Without the built-in fan base, these movies wouldn't happen," Evans told THR on the red carpet. "It's exciting to be a part of something that you know fans are going to see, that they're excited about. It's intimidating, but the truth is, Marvel has yet to let me down."

Ruffalo, who reprised his role as the Hulk, says his motion-capture work as the green superhero is the toughest on him — and his body.

"Every time I had to do the Hulk stuff, something would get pulled or sprained," he said.

Newcomer Elizabeth Olsen, who joined the franchise as Scarlet Witch, said it's just starting to soak in that she's a part of such a big, well-loved project. The actress added that she enjoys that her character doesn't fight with strength or force, but rather with powers.

"I was a dancer growing up, so I was excited to work with a dancer and learn movements," she said, adding that she loved her character's "weakness of being overwhelmed and not quite understanding how to control everything that she has. No one taught her how to use her powers, so her weakness in the comics make her a really interesting character to me."

At the screening, the cast, including other newcomers Aaron Taylor-Johnson and James Spader (who voices Ultron) joined fellow franchise stars Samuel L. Jackson and Cobie Smulders, as well as Marvel's Kevin Feige and Whedon. They took to the stage to greet the audience before the screening kicked off.

When asked by THR how Age of Ultron represents Whedon as a director, he said with a laugh: "It's a little odd. There's something wrong with it, it's a little unhinged."

He added: I'm very comfortable in the Marvel world, and I really love it there. The first one was really a meeting of the minds, and it got me enough trust to say, you know, there are characters and visual ideas and emotional journeys that I want to go on that I couldn't have done in the first movie."

After the screening, the cast celebrated with the director at Ohm Nightclub at Hollywood & Highland. Age of Ultron will be Whedon's last turn directing the ensemble-superhero franchise — at least for the foreseeable future. The Russo brothers have signed on to direct Avengers: Infinity War — Part 1 and 2.

Added Whedon: "I'm ready to do something else, something smaller."

Avengers: Age of Ultron opens in wide release on May 1.