Williams, an eight-time Grand Slam champion, will join the St. Louis Aces when they host the New York Sportimes on July 23.
Sharapova, winner of two majors and currently ranked No. 2, will play for the Newport Beach Breakers when they host the Kansas City Explorers on July 26.
Other players who have agreed to play in the July 5-25 regular season include Williams' sister Venus, Pete Sampras, John McEnroe and Anna Kournikova
According to a source in the Russian Defence Ministry, Russia started deploying elite commando units in eastern Libya. Russian GRU officers, mercenaries and advisors have arrived in Libya