Enrique Iglesias has cryptically teased he may have already married longtime partner Anna Kournikova.

The Hero singer, who has been dating the former tennis professional since 2001, has previously said he didn't think they needed to get hitched, but he sparked speculation they may have tied the knot when he cryptically discussed the topic of marriage in a recent interview.

"I don't believe you need a piece of paper to show you love someone," he told E! Online, but when he was asked if they may one day walk down the aisle, he replied, "Who knows what the future holds...or the past..." followed by laughter.

Former sports star Anna, 35, has also been seen wearing a gold band and a large diamond on her ring finger in Instagram posts in recent months.

The private couple have been dogged with marriage rumours for years but Enrique said in 2014 he didn't think a wedding would bring them closer together or make them "any happier" as they have already been with each other for so long.

He later clarified his remarks on U.S. show Today, saying, "It's not, I didn't say that I don't want to get married...What I said is that, 'We are extremely happy the way we are.' I'm not against marriage by any means."

"I have not ruled it out, but if you're happy, I don't think it will really make a difference... She's the coolest girl in the world", he explained.

The 41-year-old previously had to deny a possible marriage after he referred to her as his "wife" during a concert in 2011 and they were rumoured to be getting hitched once again in 2013, but his father Julio disputed the speculation by saying he hadn't been invited to any ceremony.

The couple met on the set of his music video Escape in 2001.