Halep reached the Melbourne title match in 2018 but lost a three-set thriller to Caroline Wozniacki. It was the Romanian's third defeat in three Grand Slam finals.
The decision marks Clijsters' second return to the sport after first retiring in 2007.
Petra Kvitova takes on Naomi Osaka in Saturday's Australian Open final with one of them set to emerge as a fresh champion at Melbourne Park.
Factbox on Romanian Simona Halep, who beat Sloane Stephens 3-6, 6-4, 6-1 to win the French Open title on Saturday:
A look at the records of Czech Republic's Karolina Pliskova and Japan's Naomi Osaka before their semi-final match at the Australian Open on Thursday (prefix number denotes seeding):
'I feel when I sort of close this chapter of my life... an Olympic medal is something that I would have loved to win. So I want to give myself another shot at it.'
Serena Williams' coach Patrick Mouratoglou has called on tennis governing bodies to come together and devise a way of helping lower level professionals struggling financially due to the coronavirus shutdown. The tennis season was halted in early March due to the pandemic, leaving players in the lower tiers who solely depend on tournament winnings without the opportunity to earn a living.
Serena Williams and Naomi Osaka have long moved on from their tempestuous 2018 US Open title match but that will do nothing to dampen the suspense ahead of their blockbuster Australian Open semi-final on Thursday.
A look at the records of Garbine Muguruza and Sofia Kenin ahead of their Australian Open final on Saturday.
Halep withdraws from Western & Southern Open with injury.
Sania is returning to the circuit after a two-year break but injured her leg in practice.
Tennis great Billie Jean King says the financial fallout from the coronavirus shutdown has exposed the unfairness of the sport and that it is important for the top players to lead the cause for change. The tennis season was suspended in March due to the COVID-19 pandemic and the shutdown will continue at least until mid-July, depriving lower-level players, who depend solely on tournament winnings, of the chance to earn a living.
India will host its first WTA tournament in five years when the city of Mumbai stages a $ 125,000 event in November, giving home players an opportunity to compete with the world's top-50.
Defending champion Novak Djokovic tops the draw while new world number one Ash Barty is top seed in the women's singles.
Wimbledon organisers will announce the cancellation of the grasscourt Grand Slam this week due to the coronavirus pandemic, German Tennis Federation (DTB) vice-president Dirk Hordorff told Sky Sports. All England Lawn Tennis Club (AELTC) officials earlier said the June 29-July 12 event would not be played behind closed doors and postponement was not without significant risk and difficulty.
Naomi Osaka has witnessed a huge change in her career after claiming a maiden Grand Slam title in 2018, but the rising star of women's tennis will not be changing her quirky personality in media appearances that has endeared her to so many.
IMAGES from Day 2 of the Wimbledon Championships from the All England Lawn Tennis and Croquet Club, London, on Tuesday.
Former world number one Garbine Muguruza was beaten 7-5, 6-4 by Aryna Sabalenka in the China Open second round on Tuesday while an ailing Jelena Ostapenko lost 6-0, 6-0 to Wang Qiang.
Russia's Daniil Medvedev remarkably reached his ninth final of the season as he defeated Stefanos Tsitsipas 7-6(5), 7-5 at the Shanghai Masters on Saturday.
Melbourne on Friday completed 28 days since the last reported locally-acquired case of novel coronavirus infection.
Kenin, who was seeded 14th last year, came back from a set down to beat Spain's twice Grand Slam champion Garbine Muguruza in the Australian Open final.
The 26-year old Stephens and Altidore, 29, announced their engagement on Monday with joint posts on social media.
Martina Hingis has announced she will retire from tennis at the end of this week's WTA Finals, where the 37-year-old multi grand slam champion is playing in the doubles tournament alongside Taiwan's Chan Yung-jan.
'I've accomplished a lot this past year and I feel I can do even more, now I actually believe I can do more after all of this success so I am going to keep striving and hopefully win many more Grand Slams. I have been thinking about playing the Olympics for a couple of years, I think it is a very special event'
Meanwhile, in the WTA event, third seeded-pair of Sania Mirza and Yaroslava Shvedova lost 3-6, 6-7(7) to second seeds Yung-Jan Chan and Martina Hingis in the semi-finals of the $3,076,495 red clay event.
Organisers in talks with governing bodies amid rescheduling reports.
The World No 1 becomes earliest qualifier for WTA Finals
When two champions of tennis share their knowledge of the sport they most love and excel, everyone is keyed in. That is exactly what happened on Wednesday evening when Indian ace Sania Mirza hosted the legendary Martina Navratilova at a tennis 'Masterclass' in Hyderabad.
The 30-year-old is the first German woman to win Wimbledon since Steffi Graf in 1996.
Could French Open champion Jelena Ostapenko serve up another shock at Wimbledon this year? Or will world number one Angelique Kerber get her season back on track at Wimbledon?
Francesca Schiavone became the first Italian woman and the oldest first-time Grand Slam winner since 1969 when she won the French Open in 2010
The Swiss re-entered the upper echelon of women's tennis at number 14 after winning the Italian Open
Former world number one Karolina Pliskova utilised her big serve to full effect to ease to a 6-4, 6-4 victory over home favourite and U.S. Open champion Naomi Osaka in the Pan Pacific Open final in Tokyo on Sunday.
Former world number one Serena Williams will not be seeded at this year's French Open, according to the organisers of the May 27-June 10 claycourt Grand Slam.
Petra Kvitova won her third title of the year as she fought back from a set down to beat Romanian Mihaela Buzarnescu 4-6, 6-2, 6-3 in the Prague Open final on Saturday.
The Indian Wells tennis tournament was set to start on Tuesday, attracts the game's top players from both the men's and women's sides and drew a record 475,000 fans over its two-week run last year. It was cancelled over concerns about the spread of a coronavirus in Southern California.
That is Murray's 46th ATP title.
It is Mladenovic's third major doubles title
The US Open has said it regrets that French player Alize Cornet was given a warning for removing her shirt during a match following complaints that the decision was sexist.
IMAGES from Day 2 of the 2022 French Open at Roland Garros in Paris on Monday.