Tom Parker Bowles says his stepfather King Charles is "strong" amid his battle with cancer.
The son of Queen Camila, 77, has admitted it's been a "very worrying" time for the 76-year-old monarch and the rest of the Royal Family since he was diagnosed with the "terrifying disease" in January, but he's doing all he can and following doctors' advice.
Speaking to PEOPLE magazine, the writer said: "The King is strong. He is doing what he can. He's following the advice of his doctors. Fingers crossed, touch wood.
"It's a terrifying disease, and when someone close to you gets it in whatever capacity, it's a very worrying thing."
Tom is "incredibly proud" of his mother for how "strong" she has been for her husband.
He continued: "But my mother is strong as well. She supports him in every way. I think it's wonderful to have someone you love by your side.
"I'm incredibly proud of her. She's at an age when most people think of retiring, but she never complains; she just gets on with it."
Meanwhile, Tom revealed he is yet to spend Christmas with the Royal Family.
The 49-year-old food critic might be the son of the queen, but he insists he and his family don't spend their time "running around palaces" and he hasn't been to Sandringham to spend to experience one of their traditional festive family meals yet.
He said: “We are married in, we are not the royal family – I’ve never for one second said that.
“I find everyone incredibly nice and friendly and we’ve know them all for a long time. It does seem natural.
“That’s not to say myself and the children spend time running around palaces.
“I have my own job and the children have school. I haven’t been to Christmas yet for various reasons.”