Nadal to make long-awaited tennis return

(CNN) -- Former world number one Rafael Nadal will end a six-month absence from tennis when he competes in an Abu Dhabi exhibition tournament later this month, the Spaniard has revealed.

Nadal has been sidelined by knee problems following June's shock second-round exit at Wimbledon to 100th-ranked Czech Lukas Rosol.

"Can't wait to get back on court in Abu Dhabi at the end of the month," he wrote on his Twitter and Facebook pages. "I won the Mubadala World Tennis Championship in 2010 and 2011 -- would love to get my hands on the trophy again this year."

After his Wimbledon exit, the 11-time grand slam champion was diagnosed with Hoffa's syndrome, an inflammation of the fatty tissue in his left knee that has sidelined him on numerous occasions over the years.

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The injury meant Nadal was unable to defend his Olympic title at London 2012, with the 26-year-old dropping to fourth in the rankings after also missing out on the U.S. Open and Spain's Davis Cup final defeat to the Czech Republic in November.

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Having started training again late last month, Nadal will make his return in Abu Dhabi on December 28, 17 days before the first grand slam of 2013 -- the Australian Open in Melbourne.

Earlier this month, he said it would be difficult to win the Australian Open after such a lengthy period off court, warning fans not to expect "miracles."

Nadal has a first-round bye in Abu Dhabi, then plays the winner of the match between U.S. Open and Olympic champion Andy Murray and ninth-ranked Serbian Janko Tipsarevic.

World No. 1 Novak Djokovic will also line up in the six-man, three-day event. He will play either world No. 5 David Ferrer or Czech Davis Cup winner Tomas Berdych on the second day.

Meanwhile, the International Tennis Federation has named Djokovic and third-ranked woman Serena Williams as its 2012 world champions.

Djokovic received the honor for the second year running, as the Serbian retained the Australian Open and won the season-ending ATP championship but suffered the disappointment of losing the final at both Roland Garros and Flushing Meadows.

"I am proud to have been named ITF World Champion for the second successive year," said the 25-year-old.

"It was very difficult to follow up such a successful season in 2011, but it was extremely satisfying to win another grand slam title, reach two other major finals and finish the year at No. 1."

Meanwhile, Williams was in vintage form in 2012 as the 31-year-old tasted Olympic singles gold for the first time in addition to taking her grand slam collection to 15 titles, following this year's triumphs at both Wimbledon and the U.S. Open.

"It means a lot to be named ITF World Champion for the third time," said Williams, who finished the season with a WTA Tour-best seven titles.

"It has been such an amazing experience this year to win the Olympics and two grand slam tournaments, and I look forward to having an awesome 2013."

It is the second year in a row that the top-ranked woman has missed out on the ITF award -- last year Petra Kvitova headed off Caroline Wozniacki.

This time Victoria Azarenka missed out despite leading the earnings list with more than $7 million in prize money and winning her first grand slam in Melbourne.

The ITF World Champions will receive their awards at a dinner during the French Open in Paris next June.