George Clooney's girlfriend Sarah Larson has revealed how the two met "three or four" years ago.

It has been originally reported that the couple met at last year's Ocean's Thirteen premiere in Las Vegas, but 28-year-old Larson claims this is untrue.

"It was on his birthday three or four years ago at Whiskey at [Vegas's] Green Valley Ranch," she said. "I was with some friends. We were all dancing, taking pictures, being silly."

Larson told the Las Vegas Review Journal how unfortunately, she was dating someone else at the time, but Clooney tracked her down when he was in town for a film premiere last summer and they have "hung out" ever since.

In a way, she was one of his birthday gifts, as the pair have gone on to become one of the most loved up couples in Hollywood.

The couple are to spend Clooney's 47th birthday in May at his villa in Lake Como, Italy.

However, Clooney has publicly denied reports that they are engaged.