World number four Maria Sharapova has announced that she has joined forces with coach Sven Groeneveld.

The 26-year-old revealed that she has been working with the Swede since returning from a shoulder injury, which kept her out of last month's season-ending WTA Championships in Istanbul.

The Russian has been without a coach since parting with Jimmy Connors in August after just one month working together.

"I'm happy to announce my official partnership with Sven Groeneveld," she wrote on her official website.

"We've been working together since I got back on the court and after seeing him on the opposing side for so many years, I'm excited to have him become a part of my team.

"It has been a very seamless transition and I have had a lot of fun with the hard work we have put in so far. Looking forward to the year ahead."

Groeneveld has coached Monica Seles, Mary Pierce and Ana Ivanovic to Grand Slam titles.