Matt Damon has portrayed many people on film, from a math whiz to a murderer, but whether he plays Robert F. Kennedy in a new movie remains an open question despite his confidence it will happen, he said on Friday.

Earlier this week, celebrity websites trumpeted headlines that Damon would soon portray the slain U.S. presidential candidate and member of the Kennedy clan, but had yet to see a screenplay. Friday, the actor confirmed those accounts.

"I haven't seen a script yet but I have been talking to (director) Gary Ross about that for over a year, and we are both really excited to do it," Damon told Reuters in an interview promoting his upcoming action film, "Green Zone."

"You have always got to wait for the script. Gary is a great writer and a great director, so I am confident that it is going to happen. The script is coming in next month."

Ross wrote and directed 2003 Oscar-nominated movie "Seabiscuit," and he is attached to direct the Kennedy film, which has yet to have a title. The movie will be based on Evan Thomas' biography "His Life" and the script written by Steven Knight, according to media reports.