LOS ANGELES?Oscar-winner Sandra Bullock has filed for divorce from her allegedly philandering husband, and at the same time has become a new mom, adopting a three-and-a-half month old baby boy, People magazine reported Wednesday.

The Hollywood gossip mag wrote on its website that Bullock has filed divorce papers to formally split from celebrity mechanic and reality-TV star Jesse James, who reportedly cheated on her for months with tattooed stripper Michelle "Bombshell" McGee.

"Yes, I have filed for divorce," the 45-year old Hollywood actress, who won her first best actress Oscar last month for her role in the hit film "The Blind Side."

She reportedly added that she felt "sad and... scared."

Bullock, one of Hollywood's most popular and most bankable actresses, cancelled public appearances and vanished from the public eye in the weeks, following revelations that her husband had strayed, and news of her divorce and new motherhood marks an emphatic return to the spotlight.

People reported that Bullock and James four years ago began the adoption process together and that they received the African-American infant, Louis Bardo Bullock, aged three and a half months, in January.

They decided to keep the news of the adoption to themselves until after the Oscars, said the magazine, which reported that Bullock now is adopting the infant as a single parent.

The magazine on its cover posts a photo of a beaming Bullock holding the baby aloft.

The magazine quotes James as saying he has a "huge hole" in his heart, but understands her decision.

"Sandy is the love of my life, but considering the pain and devastation I have caused her, it would be selfish to not let her go," he told People, also declaring his love for little Louis.

Bullock moved out of the couple's home days after winning the award, amid reports that James, 41, had affairs with at least four women, including McGee.

Shortly after the scandal broke last month, James, Bullock's husband of nearly five years, issued a statement apologizing to his wife and children, and reportedly sought in-patient treatment at a clinic.

McGee told the magazine "In Touch Weekly" that she and James carried on an 11-month affair while Bullock was shooting "The Blind Side."

James, who hosts the reality TV show "Monster Garage" has three children -- a daughter Chandler and son Jesse Jr. with his first wife, Karla James, and a daughter, Sunny, with his second wife, adult-film star Janine Lindemulder.

News reports said Bullock has helped raise five-year-old Sunny for the last several months after Lindemulder was sentenced to six months in federal prison for tax evasion.

In "The Blind Side," Bullock plays a Southern mom who takes a homeless black youth into her own and nurtures him to high school football greatness.

During her poignant Oscar acceptance speech, a tearful Bullock thanked "what this film was about for me, which are the moms that take care of the babies and the children, no matter where they come from."