Volcano ash threatens Tribeca, Cannes Film Festival

sean-penn-robert-downey-shia-labeouf-cannes.jpg Miley Cyrus and Liam Hemsworth can't get to their London premiere of "The Last Song" because of the volcanic ash flight cancellations.

And if the dangerous ash continues, it threatens to disrupt the upcoming Tribeca Film Festival in New York,  the Cannes Film Festival as well as major international film junkets.

A-list Hollywood stars including Sean Penn, Naomi Watts, Shia LaBeouf, Carey Mulligan, Josh Brolin,  Ryan Gosling and Michelle Williams all  have big films premiering at Cannes this year.

Russell Crowe and Robert Downey Jr., Scarlett Johansson and Mickey Rourke have junkets in London this weekend skedded for their films "Robin Hood" and "Iron Man 2." Both could be disrupted by flight cancellations.