With this ring, has Mick picked bride No3?

Speculation that the 63-year-old Rolling Stones singer and long-time girlfriend L'Wren Scott may be planning to wed was fuelled when she showed off a dazzling ring on her engagement finger.

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Topped by a large gem, it was seen as the 6foot 4inch stylist draped a hand over the star's shoulder at a fashion event in New York.

In recent weeks the couple, who have been together for five years, have spent many hours - and hundreds of thousands of pounds - designing a new interior for a £6million house they bought in London last summer.

Yet 40-year-old American-born Miss Scott has never until now shown off such a glittering ring.

A friend of Jagger suggested that since Sir Mick is so private about his personal life, the first the public - or indeed his managers - would hear about a marriage would be after it had happened.

"Mick's really not the sort to have some kind of engagement," the friend added. "If they were going to get married, they would probably just do it.

"Yet it is interesting that L'Wren has on this occasion - a very public event in New York - decided to wear a ring on her engagement finger so obviously."

A spokesman for Sir Mick insisted the couple have no plans to marry.

But the friend added: "At the New York party, L'Wren even seems to be showing the ring off by draping her hand over Mick's shoulder.

"If they are not engaged, then they are certainly happy for the world to think they are. They are both savvy enough to realise what speculation such a pose may attract."

Jagger has been married twice. He wed Nicaraguan-born model Bianca Perez Morena de Macias in 1971 and Texan model Jerry Hall in 1990. Both marriages ended in divorce.

The singer has spent the past four years - while not on tour with the Stones - living in an apartment at Claridges Hotel in Mayfair.

But last year he decided that the hotel bill - when it reached in excess of £1.5million - could be better spent on a permanent property in London.