Serena Williams was included on the entry list for the US Open on Wednesday as was Novak Djokovic even though his refusal to be vaccinated will bar him from entering the country.
Williams, who won the first of her six New York titles in 1999, remains frustratingly one Grand Slam short of Margaret Court's record of 24.
The American star won the last of her 23 majors at the 2017 Australian Open while pregnant. Her most recent US Open title triumph was in 2014.
Former world number one Williams only returned to singles action at Wimbledon last month after a year on the injury sidelines.
Djokovic, fresh from capturing his seventh Wimbledon title and 21st major, is on the list for the August 29-September 11 tournament, the season's final Slam event.
The three-time winner will, however, be unable to enter the United States after refusing to be vaccinated against Covid-19.
"Per the Grand Slam Rule Book, all eligible players are automatically entered into the men's and women's singles main draw fields based on ranking 42 days prior to the first Monday of the event," said a statement by the United States Tennis Association.
"The US Open does not have a vaccination mandate in place for players, but it will respect the U.S. government's position regarding travel into the country for unvaccinated non-U.S. citizens."
Men's world number one Daniil Medvedev returns to defend his title.
Medvedev and his fellow Russians were banned from Wimbledon this year as a result of the invasion of Ukraine.
They can play in New York although not under their national flag.
Women's champion Emma Raducanu and two-time winner Naomi Osaka are also on the entry list.