Rumours about Sir Cliff's private life have dogged him for decades. A relationship he has with John McElynn, a former Catholic priest who looks after his homes in Britain, Barbados and Portugal, has only served to fuel the speculation.
Sir Cliff, who first hit the charts in 1958 with the song Move It and who has now sold more than 250 million records around the world, said he had never wanted the responsibility of having a wife and family.
He said: "I just didn't get married. I never felt that it was the right time. I can do the things I want to do. I can go and meet my fans all over the world.
"I don't have a responsibility because I always felt that marriage would be the major responsibility of your life, and if a child came along, a multi-major responsibility. No getting out of that one."
Asked whether his friendship with Olivia Newton-John, the Australian singer and star of the film Grease, could ever have led to marriage, Sir Cliff replied: "Let's face it, we all loved Olivia. She had that effect.
"When she came on to do my TV show, we invited her [to appear] for one week, but she was there for about eight."
Sir Cliff, whose continued youthful looks have earned him the title the Peter Pan of pop, insists he has never undergone plastic surgery but would not rule it out.
He said: "Plastic? Well, I think it's due. When people say to me, have you had anything done, I say yes, I had these lines put in because I wanted to look older.
"I did try Botox but that didn't really work for me. I've seen people with Botox - they look fantastic.
"If it works for you, I don't see what's wrong with doing it. Why not? Women wear make-up."
Sir Cliff says his continued youthful appearance may be down to 'extreme good luck' and the fact that his mother remained young-looking.
He also says he is proud that he never adopted the hedonistic lifestyle of a typical rock and roll star.
The star said: "I've never wanted to trash a hotel room. My band always used to say, Cliff never trashes a hotel room.
"When he goes in, he usually cleans up, hoovers, checks the curtains are straight. I can't imagine anything more childish than trashing things, which is what a lot of rockers did."
- Mail On Sunday
