Amber Heard's former agent didn't expect her marriage to Johnny Depp to last because she is an "alpha female". The 'Magic Mike XXL' actress filed for divorce from the 52-year-old actor last month after 15 months of marriage and Jeffrey Nightbyrd, who was her first acting agent and is based near Amber's parents' home in Texas, was unsurprised by the news. He told Grazia magazine: "She and Johnny were always an interesting match. When two creative people like that get together romantically, they don't last. "The fact their marriage was over after 15 months is not surprising. "They are both alpha forces and there was bound to be a clash. Amber is naturally brilliant and original as an actress. She's totally bold and fearless, you could say she is an alpha female." After splitting from Johnny, Amber claimed she had been assaulted by the actor, and despite the 'Mortdecai' star's friends denying the allegations and his representative suggesting the 'Danish Girl' star was "attempting to secure a premature financial resolution by alleging abuse", Jeffrey insists she wouldn't lie about something so serious. He said: "She would not have made up those kind of allegations to hurt him. "I just don't believe that and I don't believe she would outright lie. It would be extraordinarily unlikely. "I wasn't there in the room with them so I can't say what happened that night. But from what I know, Amber loved Johnny Depp with all her heart." The 30-year-old actress is said to be concerned she is the victim of a "smear campaign" orchestrated by her estranged husband. A source said: "Amber believes she is now the victim of a smear campaign by Johnny. "She very much sick to her side of the story and now feels under threat by Johnny's campaign against her. What worries her is just how much sway he has."