Serbian tennis legend Novak Djokovic and women's No 1 Aryna Sabalenka top the list of pairings entered for the US Open mixed doubles.
However, both men's world No 1 Jannik Sinner and second-ranked Carlos Alcaraz have not entered the competition which was heavily revamped last year.
Reforms featured a shorter scoring format in the earlier rounds and a new scheduling slot – played over two days – before the singles draws in an attempt to encourage the top players to enter.
Italian doubles specialists Sara Errani and Andrea Vavassori, who criticised the changes, will defend the title they won last year, which came with a $1 million winners' cheque.
Djokovic, 39, and 28-year-old Sabalenka are certain to feature among the initial six pairings selected according to world rankings when the deadline for entries closes on 17 August.
"Anytime you can bring women and men together on the same team, you showcase tennis at its best," said US Tennis Association CEO Craig Tiley.
"This is exactly what the mixed doubles championship does.
"We are proud to again bring the world's top players together in a format that will provide exciting entertainment for our fans."
Wimbledon champion Sinner – who did not enter last year's mixed doubles – is "prioritising" his health ahead of the final Grand Slam of the year and is also bypassing the Canadian Open, which runs from 2-13 August.
Alcaraz, who did play last year with Emma Raducanu, is recovering from a wrist injury that ruled him out of both the French Open and Wimbledon.
Eight teams will be determined via wild card and announced on a date to follow. Two teams will earn a main draw spot by advancing through the eight-team qualifying draw played on 24 August.
The two-day tournament gets underway on 25 August, five days before the men's and women's singles competitions begin.