The 41-year-old Steve Waugh, renowned for his gritty approach to the game, captained Australia 57 times and achieved 41 victories -- the most by any test captain.
After making his debut in 1985, Waugh hit 32 test centuries, a mark only bettered by India's Sunil Gavaskar and Sachin Tendulkar, and led Australia to victory in the 1999 World Cup.
The family released a statement saying they appreciated the public's concern but did not elaborate on the circumstances surrounding Lynette's sudden illness.
The couple were married in 1991 and have three children.
