Clarkson played actress Madge Kendall opposite Bradley Cooper onstage on Broadway and the West End, and admits baring all in London is a much bigger deal.

She explains, "In London, there's something called the royal box and it's very, very, very close to the stage. The people watching from the royal box see everything.

"We were hoping royals would come, because I wanted Kate and William to see me. For the rest of my life, I could say, 'I've been seen naked (by royalty). The Queen would have been (amazing). I was desperate for the royals to come, but they didn't come.

"My mother sat there... and Tom Cruise came, and he remarked to me at the end that he had very good seats... So many celebrities came that at a certain point I just stopped asking."

But Clarkson admits revealing all every night did take it's toll on here, adding, "I had to be naked and cry simultaneously. I don't recommend it."