Ozzy Osbourne tipped employees in a karaoke bar for letting him use the toilet.

The Black Sabbath frontman was caught short during a trip out in New York this past week and went into Keats bar in Midtown and asked them if he could make a much-needed trip to the rest room.

Staff were more than happy to let Ozzy use the facilities and, after he'd finished up, the rocker left several notes on the bar to show his appreciation before heading out.

A source told the New York Post newspaper: ''On his way out he was being nice to all the employees and threw a substantial amount of money on the bar ... Sadly he didn't sing karaoke, but we hope he'll come back.''

Ozzy - who was in the city to promote new Black Sabbath album '13', the first studio record featuring the original members for 35 years - also refused the offer a drink from several patrons as her left.

The 67-year-old rocker started drinking alcohol and taking drugs again earlier this year after relapsing following a lengthy period of abstinence.

His behaviour led to he and his wife Sharon living separately for several months, but they are now co-habiting again and the 64-year-old rocker has been sober for over 90 days.

Ozzy and his Black Sabbath bandmates Tony Iommi and Geezer Butler are celebrating '13' - produced by Rick Rubin - going to number one in the UK album chart and the singer is stunned by the reaction to the LP.

He said: ''I'm in shock, the success of this album has blown me off my feet. We've never had a record climb the charts so fast.''