Justin Timberlake and Cameron Diaz in Bad Teacher
Gemma La Mana
03/31/2011 AT 05:20 PM EDT
and Justin Timberlake
were once a real life couple and now they're reuniting on screen – but there was nothing awkward about the former flames working together.
Being on set with Timberlake, 30, on the upcoming Bad Teacher
"really wasn't a big deal," Diaz, 38, said before accepting the award for Female Star of the Year at CinemaCon in Las Vegas on Wednesday. "We had a great time."
And the pair's shared sense of humor came in handy. "Justin and I have always had a good laugh together, and to make a movie where we get to have a laugh together," Diaz said. "There really was no one else who was more perfect for this part. That's why he got the part."
In the movie, Diaz plays a foul-mouthed teacher who sets her sights on Timberlake, a new colleague at the school.
"He's a genius comedian, everybody knows," she said. "Saturday Night Live
and all the stuff that he's done over the years, he's clearly talented. We went for the best person for the job, and it just so happened that it was him. And he delivers."