Rod Stewart surprises pub-goers by helping slammed bar staff to pour pints behind the bar

Sir Rod Stewart is not afraid to roll his sleeves up and get stuck in.

First, he got down and dirty filling potholes near his house, and now the legendary rocker has been captured serving thirsty punters their pints.

Stepping behind the bar at The Dirty Duchess on Argyle Street, the 77-year-old gave a helping hand to slammed bar staff while his football team Celtic's Old Firm Derby played against rivals Rangers.

A photo of the 'Maggie May' hitmaker was shared on Instagram showing him leaning over the taps on the serving side of the bar, engaged in conversation, as he helped pull pints.

"Great to have spare bartender Rod 'the mod' Stewart tonight!," the caption read.

Dressed up in the Celtic colours of white and green, with a green sweater vest over a white shirt and his green and white striped tie undone around his neck, there was no doubt which side the musician was on.

Too cool!