LONDON - BRITISH singer Robbie Williams 'proposed' to his actress girlfriend, Ayda Field, live on Australian radio on Friday, but his spokesman later said it was a joke.

Field was in the studio with Williams, 35, for the Kyle and Jackie O show on Australian radio station 2DayFM in Sydney to promote his new album Reality Killed the Video Star.

Presenter Jackie Henderson was telling him that Sydney has a bit of a reputation for proposals with celebrities at which point Williams turned to Field and said: 'Is there anyone you want to get married to?'

She replied: 'This is so awkward.'

To which Williams said: 'Will you marry me?'

After a pause, Field, 30, answered: 'Yes, I'll marry you.'

When asked whether Williams was serious, his London-based spokesman said: 'He did say it, but in a jocular manner. They are not engaged.'

But the singer's mother Jan later told BBC's Radio 5 Live show: "I'm very excited. I'm really pleased. They've been together for nearly three years, so it's about time."

One of Europe's most successful entertainers, Williams rose to fame as a member of the hit boy band Take That before forging a successful solo career.

The singer, who now lives in Los Angeles, has been out of the public eye in the last few years since he left a US rehabilitation centre in March 2007 where he was treated for prescription drug addiction.

His new album is his first release in three years.