The 36-year-old has not played since clinching a 23rd Grand Slam singles title 11 months ago, after revealing she was pregnant during the tournament and taking time off to give birth to her first child, Alexis Olympia in September. Williams is aiming to equal Margaret Court's all-time record of 24 Grand Slam championships.
The tennis gun played her last match in January 2017, which just so happened to be the final of the Australian Open, which she won while secretly preggo with her daughter.
Williams and Ostapenko will be the first women to participate in the 10th edition of the Mubadala World Tennis Championship, which has long marked the beginning of the men's global tennis season.
The 12-time Grand Slam champion has not played competitively since his quarter-final loss to Tomas Berdych at Wimbledon because of an elbow injury. Williams is returning to competitive tennis with an exhibition match against French Open champion Jelena Ostapenko in Abu Dhabi on Saturday.More news: Track Santa's journey around the globe this Christmas Eve
Ostapenko said, "I am thrilled to be playing in Abu Dhabi at the Mubadala World Tennis Championship".
She said that she is happy to be part of history making by making a foundation for aspiring female tennis players in Abu Dhabi.
"Last season was really incredible for me and I can not wait to continue the start of my new season at such an wonderful event".
The 23-time Grand Slam victor will take on a fellow Major victor in the form of Jelena Ostapenko on December 30, who stunned Simona Halep to win the French Open last June. A sell-out crowd of over 5,000 per day are expected to attend and experience the thrilling on-court action.