Sandra Bullock triumphed at the Oscars by winning the best actress trophy for her impressive performance in 'The Blind Side', but reports of her husband's infidelity gave her little time to savour the victory.

The star Monday left the Southern California house that she shared with Jesse James, people.com quoted a source as saying.

James had an 11-month relationship with Michelle 'Bombshell' McGee, reports dailymail.co.uk. McGee, whose whole body is covered with tattoos, told In Touch magazine that she called 40-year-old James her 'Vanilla Gorilla' and gave salacious details of their time together.

Following the reports, Bullock cancelled the London screening of 'The Blind Side'. She was expected to attend it on Tuesday with her co-star, newcomer Quinton Aaron.

Warner Brothers announced that the event and its accompanying parties were off because 'unforeseen circumstances' had arisen which meant Bullock was 'no longer available to travel'.

The actress had a string of unsuccessful relationships before meeting James, a former bodyguard to heavy metal groups, when she took her young godson to the set of his now-axed TV show 'Monster Garage' in 2004.

The couple married a year later, in July 2005 in a sunset ceremony at a ranch north of Santa Barbara attended by 300 guests. She became his third wife almost five years ago.