A royal insider thinks that Prince Harry could propose marriage to Suits star Meghan Markle by the end of this year.

According to Hello! magazine, Princess Diana's former chef Darren McGrady has said that the marriage proposal could happen after the conclusion of two big royal events this year.

McGrady, who thinks "they would have been engaged by now", predicts that the royal could ask the actress to marry him in December to avoid the upcoming 20th death anniversary of his mother. Princess Diana died in a car crash on 31 August 1997.

McGrady thinks Harry's plans will further be delayed with Queen and Prince Philip's platinum wedding anniversary in November.

"December they can announce the engagement and they'd be free to marry next year; I think that's what's going to happen. Meghan can join the royals at Sandringham at Christmas because she'll be engaged and part of the fold," McGrady told the celebrity news website.

McGrady, who is releasing his second cookbook The Royal Chef at Home, also complimented Markle and Kate Middleton for possessing qualities similar to Princess Diana.

"I think Meghan is fantastic. Everything that I've seen of her, I think she's amazing and I think Harry's picked someone like his mum," he said.

"I think Kate's beautiful, a hard worker, she looks stunning and she's doing exactly what she needs to be doing, but I think Meghan is naturally like Diana."

"She's amazing with children, she has that compassion, I think she's stunning, she's going to be a clothes horse," he said.

"I think Harry sees his mum in her and I love what he's doing with Invictus Games. I can't speak highly enough of Harry."