The Murray-Williams partnership came just before the close time of the mixed doubles draw on Wednesday and was affirmed by the 32-year-old Scottish player's representative.
The 23-Grand Slam winner Williams chose to join Murray, telling reporters after winning her first-round singles match at Wimbledon: "If you guys really want it, then maybe I will do it."
Murray and Williams are set to square off against Germany's Andreas Mies and Chile's Alexa Guarachi in the first round of the competition. Meanwhile, the previous world No.1 Murray will pair up with Frenchman Pierre-Hugues Herbert in the men's doubles.
After Wimbledon, Murray may consider a singles return at the US Open, the last Grand Slam of the season, on the off chance that he recaptures his form following right hip surgery.
Murray initially would need to complete at Cincinnati, a US Open check-up event that he won twice in 2008 and 2011.
He has delegated the US Open champion in 2012 and a short time later he defeated the present world No.1 Novak Djokovic of Serbia in the last match.
A month ago, Murray won the men's doubles with Feliciano Lopez at the Queen's Club in his first competitive event since he experienced a second operation on his right hip in January after the Australian Open, which he had cautioned could be his last vocation competition.
Murray's mom Judy told journalists that the Murray-Williams entry "looks like an extremely strong partnership."
"It is constantly hard to tell in mixed doubles because you just have them in the Grand Slams, so no one finds the opportunity to spend significant time in it or play it a great deal.
"But they have both got a form in singles and doubles, so hopefully they can be the perfect match."
Given the possibility that Murray and his brother Jamie could meet in men's doubles third round, Judy admitted that the match would torture for her to watch.
"I have been fortunate that Andy's career has been in singles and Jamie's in doubles, so for family harmony, it has been great," she explained. "But if it happens I will go to the pub, and wait for a text."
