LOS ANGLES: Penn reportedly acted the doting boyfriend at a celebration for Charlize’s mother Gerda Theron’s birthday Sunday at Spago in LA. They dined in a private room, where Charlize and Sean sat side by side. However, it was recently reported that Gerda isn’t Sean’s biggest fan. While Gerda has never minded the pair’s friendship, sources say she “begged Charlize not to let it turn romantic.” Gerda has been gently reminding Charlize that Penn just took a trip with his ex-wife Madonna to Haiti. “Charlize refuses to believe it happened,” the pal tells Star magazine.–SN