Oprah Winfrey is convinced many people still think she's in a secret relationship with Gayle King

Oprah Winfrey is convinced many people still think she's in a secret relationship with Gayle King.

The 70-year-old TV titan has faced years of false rumours suggesting she's romantically involved with her best friend even though she's been dating businessman Stedman Graham since the 1980s - and Oprah believes the gossip may never fully go away.

During an appearance on Melinda Gates' 'Moments That Make Us' You Tube series, Oprah explained: "I think we've shared pretty much everything and I would have to say, it wasn't even a matter of navigation. For years, people used to say we were gay, and listen, we were up against that forever. And people still may think it."

Gayle then joked: "I used to say to Oprah: 'You gotta do a show on this because it's hard enough for me to get a date on Saturday night with people thinking we're gay'. Because if we were gay, we'd tell you!"

Oprah went on to insist she believes the rumours started because it was previously unusual to see two women have such a close friendship.

She added: "One of the things I used to think was that people weren't accustomed to seeing women with this kind of truth bond ... "

The TV star also suggested the reason the pair has been so close for so many years is because there is no "jealously" in their friendship.

She said: "The reason why I think our friendship has worked is because Gayle is happier, not happy, but happier for me for any kind of success or victory or challenge I get through than I am for myself.

"And I feel as happy as she does - I can't be happier than, cannot surpass Gayle. You cannot out-happy her. I am equally as happy for her ... [There's not even a] hint of jealousy about anything".

Gayle added: "I just assumed everybody had a really good friend. I just assumed every woman - maybe not for men - but I just assumed every woman had at least one.'"