Robert Downey Jr says there's some 'unfinished business for Tony Stark in Avengers: Age of Ultron.
Downey Jr is set to reprise the role of Stark aka Iron Man for the first time since the billion dollar success of Iron Man 3 back in 2013.
And while Downey Jr still remains a huge part of the Avengers franchise, he admits he did wonder where they could take this character next with this new film.
He said: "I was kind of like where can you go with the first Avengers seeing him become a team player and with Iron Man 3 seeing him transcend his dependency on the tech that is keeping him alive. So I was like now what?
"But there is a lot of unfinished business, like the wormhole that opened up over New York and the threat that that sill implies. So, Tony has turned his attentions more toward a post-Reagan era Star Wars type notion. He likes to call it Ultron."
Age of Ultron is the second Avengers film to hit the big screen and comes three years after the box office success of Avengers Assemble, which went on to gross over $1.5 billion at the global box office.
Downey Jr has since enjoyed more success with Iron Man 3 - which followed a year later - and is now back in the Avengers fold with Chris Evans, Scarlett Johansson, Chris Hemsworth, Mark Ruffalo, and Jeremy Renner.
James Spader is the big new addition to the cast list as Ultron, while Elizabeth Olsen, Aaron Taylor-Johnson, and Paul Bettany are also on board as Scarlet Witch, Quicksilver, and The Vision.
And Downey Jr will be returning to the role of Iron Man later this year when filming for Captain America: Civil War gets underway. Civil War is one of the most famous Captain America storylines and will see Downey Jr step into this franchise for the first time.
The movie will see Steve Rodgers and Tony Stark on opposing sides of the government act to regulate superhuman activity - resulting in the former allies going head to head.