Meghan and Harry will officially step down from their positions as senior royals at the end of March, and start their new independent life on 1 April - moving to spend more time in Canada and the U.S. as well as the U.K.
Helen, who won an Oscar for her portrayal of Harry's grandmother Queen Elizabeth II in 2006's "The Queen", is delighted that the couple are making the right decision for themselves, but is sad the royals have lost a "charming" addition to their number.
"I think their instincts are absolutely right, and I applaud them for it," she tells Variety at the Berlin Film Festival. "Hugely actually. Of course, it is complicated."
"Meghan Markle was a fantastic addition to the royal family - charming, did everything right, was gracious, was sweet natured, and seemed to be ... Wow! What a lovely addition. Didn't seem to be neurotic...So, I think it is a loss in a way, but at the same time I think their instincts are absolutely correct."
The couple's decision came after they had been at war with the British media over its treatment of Meghan, due to a slew of negative newspaper articles, including many focusing on her relationship with her estranged father.
Helen blames the media for driving her away from royal duties - and jokes that she'll probably be next in the U.K. tabloids sights.
"I think it will all, hopefully, sort itself out, and the tabloid pearl-clutchers will get over their trauma at not having someone to attack all the time. They'll find another victim... probably me," she adds.
The 74-year-old is receiving an Honorary Golden Bear award at the German movie event, which concludes on Sunday, March 01.