Anna Kournikova and Enrique Iglesias have had twins following secret pregnancy

Former tennis player Anna Kournikova and singer Enrique Iglesias. Photo / Getty

Anna Kournikova and Enrique Iglesias are now the proud parents to twins, according to US reports.

The former tennis ace, 36, gave birth to boy called Nicholas and girl named Lucy in Miami on Saturday, TMZ says.

Anna Kournikova and Enrique Iglesias. Phtoo / Getty

The pair have been romantically involved since 2001 and despite rumours they're married, Enrique has insisted that is not the case, The Sun reports.

Earlier this year, Enrique admitted his dad Julio still hadn't met Anna, saying: "They still haven't met, no. They have to meet at some point."

The Hero singer referred to Anna as his wife during a concert last year and she has been pictured wearing a gold band on her ring finger, but Enrique poured cold water on the idea.

He said afterwards: "We're just as happy. There comes a point when you've been with someone for a certain amount of time that I believe that you are like, married. I guess the only difference is that we haven't walked down the aisle."

The couple, who met on the set of the video for his 2001 hit Escape, are very private.

However, in an interview with Metro, he did give a small insight into their sex life, revealing it to be quite normal.

He explained: "I've never had sex anywhere weird, well, what I'd consider weird. I don't know, like in the doctor's office."