The Black Eyed Peas star – who has stood by her actor spouse despite allegations he slept with a stripper, a story he has denied – openly admits to being bisexual and says she had to learn she couldn't have extra-marital affairs with either men or women.

She said: "I've been very honest with him from the get-go. I think women are beautiful, I've had a lot of fun with women, and I'm not ashamed of it. The problem is that I also love a well-endowed man. But just because I enjoy women doesn't mean I'm allowed to have affairs in my relationship.

"I learned through talking with my therapist that it is still cheating even if it's with girls, so there is a rule there."

Despite her urges, Fergie has ruled out ever having a threesome.

She added to America's Advocate magazine: "No, that's not happening. We're too smart for that. We've done some filming but with no tape in the camera."

The couple's marriage was recently rocked by allegations the 'Transformers' star had cheated on his wife with a stripper.

However, both Fergie and Josh - who married in January - have branded the claims of infidelity as "ridiculous" and have since put on a show of togetherness.