The two stars went public with their friendship last month after staging a slumber party at a hotel in Los Angeles and posting pictures of their antics online, reported The New York Post online.
A new report suggests Gaga has now taken their relationship to a professional level by inviting the actress to collaborate on a music video for an upcoming single from her new album Artpop.
"Lady Gaga and Lindsay caused a stir last month when they had their 'sleepover' at the Chateau (Marmont hotel) and now it turns out that Lindsay will be starring in Gaga's new video from her upcoming album.
Due to Gaga's superstar status, this would be Lindsay's biggest (role) by far in many, many years," a source said. Lohan has been making a comeback in recent months after several years in and out of jail and rehab.
She is playing Dame Elizabeth Taylor in TV biopic Liz & Dick and starring in new film "The Canyons". Ironically, Lady Gaga has a role in Robert Rodriguez's forthcoming "Machete Kills" - the sequel to Machete, the 2010 film which featured Lohan as a gun-toting nun.