The 57-year-old British actor confessed to dressing exclusively as a girl from the age of six until he was 14. He told The Sunday Times Magazine: "I really wanted to be a girl. Thank God the world of now wasn't then, because I'd be on hormones and I'd be a woman. After I was 15 I never wanted to be a woman again."

The openly gay star believes parents who take the medical steps to help their children change sex are acting too hastily, and claims some children go through phases, just like he did.

"It’s nice to be allowed to express yourself, but the hormone thing, very young, is a big step," Rupert explained.

"I think a lot of children have an ambivalence when they’re very young to what sex they are or what they feel about everyone. And there should be a way of embracing it.”

The My Best Friend's Wedding star also revealed in the candid interview published that he believes former Olympian and Keeping Up With The Kardashians star Caitlyn Jenner, who was known as Bruce before she transitioned last year (15), had "no clue" about what being a transsexual involves.

"When she (Caitlyn) discovered everyone was either a drug addict or a prostitute, she was absolutely horrified," he said. "I don't think she's a woman. She's a cross-dressing man."

Rupert, who is currently starring in the third season of British TV series The Musketeers, also confessed he and a former girlfriend, French actress Beatrice Dalle, had a pregnancy scare.

"She and I often talk about what would have happened if we’d both had this child. And I would have loved to have had that child, actually. God, it probably would have been in rehab by now," he joked.