Sir Rod Stewart's 80th birthday celebrations will last "several weeks"

Penny told Britain's HELLO! magazine:" The celebrations will go on for several weeks.

"We'll start in Florida for Christmas and then go on a big ship together, heading to the Caribbean.

"It will be a wonderful journey."

Rod was diagnosed with thyroid cancer in 2000 and prostate cancer in 2016, and still undergoes regular checks to stay on top of his health.

He said: "I regularly undergo the most advanced medical tests, scans, and CTs.

"I consider myself lucky; my medical results are top-notch."

The 'Sailing' singer wanted to be open with fans when he was having cancer treatment because he thinks it sets a good example when people like him and King Charles - who has been receiving treatment for an undisclosed form of the disease - show they can still lead a normal life.

He said: "I went on stage during my cancer treatment and King Charles is also resuming his engagements.

"He loves what he does and it gives him strength.

"He's a great man who's done so much good for the royal family. I love him.

"The most important thing is to go for check-ups. You shouldn't hide when, like him - and also like me - you're in the public eye.

"The message it sends is so significant; life can go on, even with cancer.

"I look forward to everything to come. My journey is far from over."

Rod values his "special" relationship with the king.

He said: "It's very special. I wouldn't say we're close to the king, but we have good conversations.

"We've been working for his charity, the Prince's Trust (now The King's Trust) for 20 years."