Franco and Miller filming in Niagara Falls on July 13.
Sienna Miller did not dump her beau, Jude Law, and start up a romance with her latest leading man, James Franco, with whom she's been photographed recently, sources close to actress tell PEOPLE.
"The pictures of Sienna were of her doing a scene at Niagara Falls with James. There were about a thousand people around them and it was a sad scene, the last scene of the movie," her rep, Ciara Parkes, tells PEOPLE, referring to photos of the couple seen laughing together. "They are just joking about during takes."
Miller, 24, and Franco, 28, have been shooting their film, Camille, in Canada for the past month. Photos of them together have sparked rumors of an affair. Meanwhile, Law, 33, has been filming My Blueberry Nights in New York.
Miller and Law were spotted together in the Big Apple several weeks ago but haven't been seen together since. Still, friends of Miller insist that work demands have kept them apart, and that there is no rift between them.
"Sienna and Jude are still very much an item," says a close friend of Miller's. "Just because they are working in different locations doesn't mean they've split up."
"She and James are friends and even actors are entitled to have friends," adds the pal.
As for Miller and Law's seemingly volatile relationship, one of his pals puts it in blunt terms: "The impression I get is they can't be together and yet can't be apart. It's quite romantic, actually."