The U.S. Tennis Association gave all of its other wild cards for singles play to Americans.
Clijsters, 37, is a four-time major champion and former No. 1 who came out of retirement this year after already being elected to the International Tennis Hall of Fame. The US Open -- which she won in 2005, 2009 and 2010 -- would mark her first Grand Slam appearance since a second-round loss at Flushing Meadows in 2012.
Murray, 33, who also has been ranked No. 1, won the first of his three Grand Slam titles at the 2012 US Open. He is working his way back from two hip operations and has not played in an official event since the Davis Cup last November.
The WTA and ATP tours were suspended in March because of the coronavirus pandemic. The women's tour resumed this week in Palermo, Italy; the first men's tournament is later this month.
The US Open is scheduled to start Aug. 31 without spectators.