Sir Rod Stewart has joked he’s going to undergo penis enhancement surgery.

Rod Stewart

Rod Stewart

The 75-year-old rocker was recently told he’ll be taller after undergoing a corrective ankle fusion operation, which helped straighten the bones in his lower legs, and joked his manhood will be the next part of him to be improved.

He said: “My knee got fixed with a knee replacement, so then the ankle didn’t know what was going on because obviously it’s crooked because of the knees, so now I’ve had to have the angle done.

“So when this is all done, I should have a nice straight leg and be able to run - and then I’m going to get my knob done.”

When asked by Virgin Radio DJ Chris Evans what needs addressing about his penis, he said: “Mind your own business!”

Rod – who has eight children, including two sons, Alistair, 14, and Aiden, nine, with wife Penny Lancaster – has blamed his passion for playing soccer for his leg issues due to the “awful” dry pitches he runs on in the US.

He said: “First of all it was my knee as I played football all my life. I’m suffering for it now.

"My knee got fixed with a replacement and then the ankle did not know what was going on.

"It was crooked. So I have had to have an ankle fusion. So when this is all done I should have a nice straight leg and I should be able to run.

"My leg has been caused by playing on awful pitches in Los Angeles. They are bone dry."

Meanwhile, Rod revealed last year that he'd beaten prostate cancer after a secret battle with the disease.

And Penny subsequently admitted it was a "terrible time" for their whole family.

The model - who has been married to the music star since 2007 - said: "It was awful, such a terrible time. It was the shock of it.

"Rod isn't like one of those men who will never go to the doctor. He has more check-ups than anyone I know.

"And yet, when they picked it up, it wasn't just contained in the prostate. It had come through - but, thankfully, not to the point where it spread throughout his body."