Kim Clijsters: I've had more energy these last six months or so than I've had in the last two years because I'm taking care of myself better. (WTA)

Four-time major champion Kim Clijsters is set to come out of retirement and return to the Women’s Tennis Association (WTA ) Tour in 2020.

The 36-year-old Belgian, who retired after the 2012 US Open, announced the news on Thursday.

“I don’t really feel like I want to prove something,” Clijsters said on the WTA Insider Podcast. “I think for me it’s the challenge.

“I have friends who would say, I want to run the New York Marathon before I turn 50. For me, I still love to play tennis. Whenever I’m at a Grand Slam playing the Legends, if somebody asked me hey, do you want to hit some balls, I’m the first one to be like I’ll hit. I’ll be the hitting partner for your practice today. I still love playing tennis.

“The love for the sport is obviously still there. But the question still is, am I capable of bringing it to a level where I would like it to be at and where I want it to be at before I want to play at a high level of one of the best women’s sports in the world.

“I don’t feel like I need to prove anything, but I want to challenge myself and I want to be strong again. This is my marathon. This is where I’m saying OK, let’s try this.”

This marks the second time in the Belgian’s illustrious career that she will return to the tour after an extended hiatus.

Clijsters turned pro in 1997 and first reached No.1 in 2003. Two years after winning her first major at the 2005 US Open, Clijsters stunned the world when she announced her retirement at the age of 23 due to injuries and to start a family.

Clijsters was back on the circuit two year later. In the interim, she gave birth to her daughter Jada in February of 2008, and she came out of retirement to play her first tournaments in August 2009 at the Western & Southern Open and Rogers Cup, immediately tallying two Top 10 wins.

Then, in just the third tournament of her comeback, Clijsters won the 2009 US Open as an unranked wildcard. En route to the title, Clijsters defeated Venus Williams, Li Na, Serena Williams and Caroline Wozniacki to capture the second major title of her career and become the first mother win a major title since Evonne Goolagong Cawley in 1980.

Clijsters followed up her US Open title by adding five more titles in 2010, including the successful defense of the US Open. The Belgian won the third major of her comeback at the 2011 Australian Open and rose to No.1 a few weeks later, returning to the top spot for the first time since 2006.

Kim Clijsters announces her return on Instagram.

Notoriously friendly, down-to-earth and a favorite among her peers in the locker room, Clijsters hung up her racquet for good—or so she thought —after the 2012 US Open.

In all, she amassed 41 singles titles in her career, including four majors, three WTA Finals titles (2002, 2003, 2010) and held the No.1 ranking for a total of 20 weeks.

After retiring, she returned to Belgium with her husband Brian, gave Jada two younger brothers, continued her work at her tennis academy and joined Eurosport as a commentator.

In an interview on the WTA Insider Podcast, Clijsters said the idea of returning to the tour had been percolating for the last two years.

“Over the years I sometimes played with the idea but then I was like, No this is impossible,” Clijsters said on the WTA Insider Podcast. “My life is here at home now and with the three kids, my youngest needs me the most. I couldn’t see that being a part of my life.”

But with her youngest son Blake set to start nursery, the impossible became more possible after a family trip to the Australian Open in January.

“That was the first time we were able to talk to our kids about how we were able to do that with Jada back in the day. I would talk to Jada and ask her, Jada, do you like this lifestyle? ‘Yeah I love it!'”

Unable to shake her desire to return to the tour, Clijsters took advantage of the growing amount of free time on her hands with the kids now off to school. Working on her fitness became the perfect escape from the routine of “Mom Life.”

For the naturally gifted daughter of two top-flight athletes, putting her body through the fitness ringer became her self-care.

“Especially since the last birth, I worked out a bit here and there but it was nothing consistent going on. It was whenever I had time, between the kids and the Academy. Just balancing everything, I just didn’t feel like I had the time to even just take proper care of myself.”

In the build-up to what will be her pre-season, Clijsters says her focus has been on fitness over tennis. Reunited with her fitness trainer, Sam Verslegers, she has seen her strength and flexibility increase and her reaction time, which she said was non-existent when she first began, has come back quickly.

Kim Clijsters celebrates 2010 US Open title with then two-year-old Jada.

In order to accommodate her family, Clijsters says she will not play a heavy schedule and will remain flexible in her scheduling to accommodate any last-minute needs at home.

For now, Clijsters is training with a January return in mind, but she is adamant that she has no desire to rush a return. She will come back when she is ready to go.

“We can talk about the start of 2020 and see where can we get a wildcard, but if I feel in December that I’m not even near to where I want to be, then I’m not going to go just for the sake of going somewhere. I want to feel like I’m getting to where I want to be.

“I still have three and a half months before and so I still think I can have a lot of improvement to go through in these next few months and that I look forward to seeing where that will lead me.” (WTA)