The 65-year-old hitmaker said he works hard to stay looking young.
Rod, who is expecting his second child with wife Penny Lancaster, told British newspaper The Daily Mirror: 'I work like a dog to look like this, there's no easy option - I'm obsessed with my health.
'But the thing is not to worry about age, I don't give a toss about getting older, I like it as long as I'm healthy.'
He added: 'My skin is good because I have had a facial every week for 30 years.'
But Stewart admits he does let himself have a special treat.
He added: 'I have a couple of glasses of wine every day after 7pm.'