MELBOURNE Grand Prix celebrations turned sour last month when winning driver Jenson Button had a bust-up with billionaire sponsor Sir Richard Branson over his  lingerie model girlfriend.

The pair clashed when Button thought the Virgin boss was coming on
to his 24-year-old partner Jessica Michibata, during a boozy dinner at
upmarket Melbourne restaurant Nobu.

"Richard was clearly very, very drunk and took a shine to Jessica during the evening," a source said.

"But there was a misunderstanding and Jenson became angry. The whole thing got very, very heated.

"Richard thought Jenson was over-reacting, and gave as good back. Both of them were livid."

Brawn team officials and Virgin executives watched the confrontation in "stunned silence".

The
blow-up reportedly happened only hours after Sir Richard, 58, announced
a sponsorship deal to put Virgin
s logo on the side of Button
s car.
Button, 29, won in Melbourne and in Malaysia a week later to help improve relations with his new sponsor.

"This was before Jenson and the Brawn GP team won in Melbourne and Malaysia, and they were an untested team looking for sponsorship," the source said.

"So for Jenson to lose his rag at Richard, it was serious. But things were fine by the next day."

Sir
Richard, worth more than $6 billion, is married but frequently
surrounds himself with glamorous women to promote the Virgin brand.