Sean Ghent, who until recently was employed by McCartney, told the British tabloid Sunday Mirror that while it is Mills who has been vilified in the split, he sees her as a victim of her husband's cold and cruel behavior.
He told the paper that he was present when Mills learned that McCartney had cut off her bank and credit cards; she was buying a train ticket and her bank card was rejected. McCartney also cut off her account at a local market.
Ghent, a former soldier, also claims that McCartney was frequently depressed and the former Beatle's abuse of alcohol and marijuana was a key factor in the marital split.
Mills "is one of the most impressive people I have ever met and has been a huge influence on me," Ghent told the paper. "I want people to understand some of that. I don't get why the British public are so down on her. She's made a success of herself against all the odds. She just wants to influence change and to inspire people.
"You don't see her shopping on Bond Street or dressed in designer clothes. But she seems to be a hate figure just because she married a British icon."
However, British celebrity columnist Neil Sean told CBS News Correspondent Mark Phillips that he remains skeptical about Ghent's claims.
"This guy has come out of the woodwork. We didn't know that much about him. If you look at the period of time he's actually worked for the family, it's amazing the things that he's claiming … slightly dubious, I think."
Mills has enjoyed some good press in the U.S. lately as the most recently-departed contestant on ABC's "Dancing With the Stars." Although she has a prosthetic leg, Mills amazed American viewers with her graceful -- and sometimes acrobatic –- moves.
But benevolence towards Mills, who was described on the show as an "animal rights campaigner," apparently does not span the Atlantic.
Ghent "talks in his interview about [McCartney] being depressed," Sean said. "Wouldn't you be, living with Heather?"