The actress won the Best Actress trophy at this year's ceremony but her marriage is on the rocks after a tattoo model claimed that she had a long affair with her husband, Jesse James, reported Daily Mail online.
The Miss Congeniality star is among a string of Oscar winning actresses whose marriage ended soon after they won the coveted award, with some other examples being Kate Winslet, Halle Berry [ Images ], Angelina Jolie [ Images ], Hillary Swank and Kim Bassinger.
Bullock has cancelled the British premiere of The Blind Side amid the infidelity claims, which come just days after she picked up the coveted golden statuette.
In a gushing speech which recalled Winslet's tribute to Sam Mendes when she took the same award last year, the 45-year-old actress had thanked motorbike enthusiast James for his support.
His eyes welled with tears as she spoke of her love for him, but according to In Touch magazine he betrayed her by having an 11-month relationship with bombshell Michelle McGee.
The model whose entire body is covered in tattoos told the magazine that she called 40-year-old James her Vanilla Gorilla and gave salacious details of their time together.
The magazine has claimed that James continued to be in touch with McGee and sent her a text message as recently as Sunday telling her that he missed her.
The model claimed that she had met and bonded with James's five-year-old daughter Sunny, by his second wife, porn star turned director Janine Lindermulder. Bullock who won a string of awards for her performance in The Blind Side had dedicated them to her husband.
"To my husband, there's no surprise that my work got better when I met you, so thank you," she said at the Golden Globes. And finally, at the Oscars [ Images ], she thanked her late mother Helga for sending her James.
A spokesman for the actress refused to discuss the magazine allegations and Jesse James was unavailable for comment.
Photograph: Danny Moloshok/Reuters