Are Lady Gaga, Celine Dion, Aya Nakamura going to open the Olympics ceremony?

World-famous stars are in line to perform at Friday's opening ceremony of the Paris Olympics, which will take place along the Seine river.The exact line-up is a tightly guarded secret, but here are three performers strongly rumoured to be appearing:Lady GagaOne of the world's biggest-selling artists, pop queen Lady Gaga − real name Stefani Germanotta...