Andy Murray is not renowned for happiness.

The former world number one often cuts a grumpy figure on and off the court, despite actually possessing a solid humour game.

And he played up to his sullen persona with a post on Instagram to sort-of-celebrate turning 31, showing him scowling while wearing a quirky hat:

I love birthdays.

A post shared by Andy Murray (@andymurray) on

“I hate birthdays,” was the accompanying caption.

Murray is continuing his recovery from hip surgery, with the three-times Grand Slam champion hoping to return in time for the grass-court season.

He has dropped to 45th in the world, with Kyle Edmund replacing him as British number one.