Beyonce has revealed she is finding it hard to play sexy in her latest film. The singer admitted co-star comic Steve Martin makes her laugh so much she finds it hard to be sultry shooting scenes for the new Pink Panther movie. Beyonce said: "In the beginning I was really nervous. Now we're having more fun, I'm having more fun, and in the past couple of scenes it's been really difficult for me to keep a straight face." "There's one scene where he's drinking a flaming mojito, and I have to stay in character, and I'm trying to be sexy, and it was really difficult..." Meanwhile, the beautiful singer wasn't fazed to be mistaken for fellow diva Jennifer Lopez by a shocked fan in New York. The dark-haired beauty, dressed in jeans and jumper, was spotted by a passer-by getting out of her Mercedes. The excited woman called out: "Oh my God, J.Lo you are so gorgeous!." A smiling Beyonce shouted back to the fan: "Thank you. But my name isn't J.Lo. It's Beyonce."