Rod Stewart refused to give up playing soccer until it became ''absolute misery''.

The 70-year-old rocker ignored doctors' orders to give up his passion for over a decade, but had to quit the sport in 2013 after suffering a knee injury and still misses it ''desperately''.

He said: ''I miss it desperately. For 13 years, I had doctors telling me I had to stop immediately. I did it until it became absolute misery.''

And though he no longer plays full matches anymore, the 'Maggie May' hitmaker - who has eight children from various relationships - still can't resist a kickabout at home with his young sons Alistair, nine, and Aiden, four, who he has with wife Penny Lancaster.

Explaining a recently-completed workout involving a 30-minute bike ride and a lengthy swim, he added to Rolling Stone magazine: ''I thought afterward, I'd just have a nice little sit in the sun.

''Then Alastair came down with his Celtic soccer ball and said, 'Come on, Dad. Let's go in the pitch!' I said, 'Oh, f**k, OK. Go and get me cleats, son. I'll be right there.' ''

Rod never expected to have more children late in life, but is glad he did and is incredibly happy with 44-year-old Penny, who he married in 1999.

He said: ''Having kids at my age was the last thing on my mind. But when you get married, women generally want babies. We're madly in love. Life is good.''