Sir Rod Stewart paid £25 for an impersonator to wish his son a happy birthday

In the clip, Rud said: "Hello Liam, Rud Stewart here, how are ya? I've got a message here for you from Penny Lancaster - not too shabby ... Happy Birthday Liam, you’re in my heart. Remember, no matter how old you feel, you’ll never be as old, p***** up or washed up as me ... This is for you, from Rod and Penny."

And Rud - whose real name is Michael Dean - then belted out Rod's hits 'Have I Told You Lately That I Love You' and 'Da Ya Think I’m Sexy?'.

Meanwhile, Rod previously ruled out having any more children.

The musician - who has eight children in total - admitted: "Sex at one point was beginning to be boring, late 80s, early 90s, always flying in models left, right and centre. One would arrive, the other would leave. It just became I was getting lonely. I thought, ‘You’ve got everything - women, great success, kids’, but there wasn’t a devotion, someone I could be devoted to, so I got bored of it. My cue is back in the rack, the banana’s back in the fruit bowl."

And Rod admitted fatherhood is "wonderful.

He gushed: "I didn't think I was going to have two more children and they're the world to me. They're both football daft Celtic supporters - even the little one goes to school in his shirt. So being a father again late in life, for me, was wonderful."