What is taking so long for Matt Damon and Ben Affleck to work together?

It's been 20 years since the duo, Matt Damon and Ben Affleck was last seen together in 'Good Will Hunting' which gave them an Academy Award for Best Original Screenplay. The pair is all ready to work together again, so why it hasn't happened yet?

The 46 year-old, who is busy in promoting his latest offering 'The Great Wall' said, "It would have to be something that we felt was really worthy of getting made. We would love to work together again and we have a company together and we develop stuff together, but to find the right thing is tough," reports E! Online.

The 'Jason Bourne' star believes that being friends is not the only reason to work with someone but, it requires something greater to do a movie together.

On a related note, he also said how proud he feels to see Ben's younger brother Casey Affleck being up for Best Actor trophy at the Oscars.

"I met him when he was five. It's wonderful, it's great. But I've felt for 25 years that he's one of the best actors on the face of the earth. And so, it feels so deserved, and so earned. Ben and I both are really thrilled. I just saw Ben the other day for the Super Bowl, and we were talking about how excited we are for him because he's really put in the work, and he's a great actor. And that performance is a great performance. It really is everything I love about acting-it's subtle, but it's real and it's still incredibly interesting. You can't take your eyes off him when he's onscreen, but he is not showy," he said.

Damon's next project is 'Witness for the Prosecution' with Ben, who is in talks to direct and star in the adaptation of Agatha Christie novel of the same name.