Sir Paul McCartney asked Heather Mills' personal trainer if they are dating, it has been reported.The Beatles legend called Ben Amigoni, 22, to ask if he was romancing his estranged wife and even invited him to his house for a talk. Personal trainer Ben, who was hired by Heather two months ago and recently became her bodyguard, told Paul there was nothing going on. A source told Britain's Daily Mirror newspaper: "Ben got a phone call out of the blue. He couldn't believe that Sir Paul was phoning him, let alone what he was asking him. Sir Paul said if Ben wasn't comfortable talking on the phone, he could come to his home for a chat. Ben denied there was anything going on and felt embarrassed about the whole thing. He didn't think he needed to go and visit Paul."Paul, 64, reportedly became suspicious after Ben split from his long-term girlfriend, Joanne Bradford, just days before travelling to the US with Heather on a charity business trip. Ben has been staying at Heather's barn conversion and friends say he has been a "rock" during Heather's public divorce battle. The brief conversation is said to have reassured Paul that Heather and Ben's relationship is a professional one.The source added: "Paul doesn't believe anything is going on. He knows Heather has to work closely with her personal trainer to keep the muscles in her leg strong. "A spokesman for Paul declined to comment.