It's not every day a couple goes diamond ring shopping in one of the world's most exclusive hotels. But that's exactly what tennis star Roger Federer and long-time girlfriend Miroslava Vavrinec were spotted doing at the brand-spanking-new Atlantis last weekend.

The couple browsed a selection of diamond rings, necklaces and bracelets in the swish jewellery store Levant.

In an exclusive interview, chairman and owner of Levant, Arif Bin Khadra told tabloid!: "He's a regular client and a close friend. I invited him over to see our new store at the Atlantis and he came to congratulate us."

Questioned about whether Federer was buying an engagement ring, Khadra remained resolutely coy.

"He was in the store for about an hour and was looking at a range of items for his girlfriend. He's a regular client."

But fans confirmed that the star was looking closely at the rings.

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"He was looking at a ring with a large stone," said a shopper at the hotel.

One of the items that Federer looked at was a 60 carat D-flawless diamond ring — the biggest diamond on sale at the hotel — and another was a 15 carat pink cushion-cut diamond ring, according to Khadra.

Fans of the star said he looked particularly dapper in a smart shirt, jeans and retro Nike trainers.

Federer and Vavrinec met at the 2000 Sydney Olympics where the pair both represented Switzerland in tennis. Romance blossomed and the two have remained inseparable ever since.

Vavrinec — a 30-year-old blonde beauty — retired from the game in 2002 following a foot injury. She is a firm supporter and manager of her beau and regular at his matches.

So could a wedding be on the cards?

While the notoriously publicity-shy pair may not spill the beans anytime soon, tabloid! will be sure to keep you posted.