The world No.7 Australian and his British bride, who wed on the last day of Wimbledon in mid-July, were one of 13 teams added to the draw for the event.
Venus Williams is partnering with Alexander Bublik for the tournament that was overhauled last year, with a $A1.4 million prize to the winning team, in an effort to get top singles players to compete.
Top-ranked Aryna Sabalenka and her partner, 24-time Grand Slam singles champion Novak Djokovic, headlined the initial list of 16 teams who entered, along with Iga Swiatek and Casper Ruud, Elena Rybakina and Taylor Fritz, and Japanese duo Naomi Osaka and Kei Nishikori.
Elina Svitolina and her husband Gael Monfils, who is expected to play his final Grand Slam event at the US Open have also entered.
Teams can enter until August 17, when the six duos with the best combined singles rankings at the time will be automatically entered into the main draw.
Eight teams will be given wild cards by the USTA, and two other teams will play their way into the field through a new qualifying tournament to be held August 24.
The mixed doubles takes place on August 25 and 26 before the main singles tournament begins on August 30.
Sara Errani and Andrea Vavassori are the two-time defending US Open champions. The Italians needed a wild card to get into last year's event because their singles ranking was too low, and that will be the case again this year.
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