Former world number one Kim Clijsters has announced a shock comeback to tennis at the age of 36.

It will be a third playing career for the popular Belgian who initially retired in 2007, returning two years later following the birth of her first child and winning three Grand Slam titles before hanging up her racket again in 2012.

Clijsters has since had two more children but in announcing her return she revealed she had been inspired by the success of mothers on tour, such as her contemporary Serena Williams.

Clijsters said: "At 36 years old I feel like I'm too young to be retired and, with so many inspirational athletes and moms competing, I can't wait to get back on the match court and see what's possible after having three children."

Clijsters has been in training since the start of the year and tested her fitness in singles at the test event for the Court One roof at Wimbledon in May.

She is planning to return to the match court at the start of next season, saying: "While there is a lot of work ahead of me in the next four months, my biggest motivation is the personal challenge involved - both physically and mentally, I want to test myself again."