Kim Clijsters is expecting her third child, the former world No. 1 announced this week. "Nr 3 is on the way," Clijsters wrote on Twitter.Her husband, Brian Lynch, also confirmed that the couple was expecting an addition to the family. The couple has a daughter, 8-year-old Jada, and a son, 2-year-old Jack, who was born following Clijsters' retirement in 2012.