The singer - who was allegedly dumped by Jen for his love of Twitter - is using the former Friends star as a conversation starter with star-struck admirers, according to U.S. reports.

"John's been recording in a studio and coming on to almost every woman in the vicinity," an insider told the National Enquirer.

The insider adds, "He goes on and on to these women about how clingy and needy Jen is. "He says that when they got back together after their first breakup last August, it was agreed she would back off on the smothering."

The source continues, "When someone tries to change the subject, he goes back to Jennifer, claiming she was so emotionally dependent and demanding that he couldn't take it.” Meanwhile, it is claimed that Jen has fallen for the ample charms of hot Scot Gerard Butler.