The 77-year-old was visibly emotional as she picked up the honour following the recent death of her husband.
Distinguished actress Julia McKenzie, who played the Queen in the 2012 Olympics opening ceremony James Bond clip, has returned to Buckingham Palace to collect a CBE.
TV’s Miss Marple said she was “very happy and also very sad” to pick up the honour for services to drama following the recent death of her husband.
Visibly emotional, the 77-year-old said: “I was so surprised at my stage of life to get anything but I’m very happy I did.
“I was very happy and also very sad as my husband died recently and he wasn’t with me. I’m sure he would have been proud.”
Julia, who played Agatha Christie’s elderly sleuth from 2008 to 2013, added that the Prince of Wales was “very sweet” as he presented her with the award the day before he walks Meghan Markle down the aisle.
She added she was “absolutely looking forward to” the royal wedding on Saturday, saying: “I expect a wonderful parade.”
The director, singer and star of many musicals also touched on the high-profile #MeToo and #Timesup campaigns against sexual harassment, triggered by the Harvey Weinstein revelations and abuse of power in Hollywood.
She said: “It’s a start, isn’t it? It’s a start. Perhaps people will think twice before bad behaviour. I think it’s a very difficult subject that will probably in some form always continue.
“Women are more aware of the support for each other and that’s been a good thing.
“It’s very difficult for women in the business per se but I think if you’re beautiful it must be very difficult. I’m what you call a character actress, so I’ve never really been in that position, but it must be awful for them.”
On playing the Queen alongside Daniel Craig for the Olympics, she said: “(Laughing) It was all supposed to be a big secret but it came out after. I was sworn to secrecy … it was such a unique job.
“So, yes, I’ve been here before to be fitted with the dress and everything like that.
“Charles was very sweet. I sung for him at St James’s Palace when he gave a party for the Queen’s 50th anniversary of acceding to the throne.
“A lot of people did a sort of cabaret of things that were playing when she came to the throne and I did a bit from Guys and Dolls.”
Julia added she was considering bringing the curtain down on her illustrious career.
She said: “I’m thinking I might retire, I don’t know. It’s been a wonderful, wonderful career, I’m so thankful.
“But I think knowing when to go is a good thing and maybe I should go now.
“Maybe a couple of months off and I’ll be raring to go again, but at the moment I just want some quiet.
“You’re terribly fortunate in this business to be in the right place at the right time and I’ve had some wonderful roles in my life.”