It has been confirmed that the traditional final Grand Slam of the year will take place on August 31.
The tournament will be held without fans due to the coronavirus pandemic and it is also expected there will be limits on the number of support staff allowed for each player.
Several players have criticised the decision to play the US Open, with Nick Kyrgios calling it “selfish”, but six-time champion Williams says she “really cannot wait to return to New York and play the 2020 US Open”.
"I feel the USTA [United States Tennis Association] is going to do a really good job of ensuring everything is amazing and everything is perfect and everyone is safe...I will certainly miss the fans, don't get me wrong.”
In preparation for the event, US Open tournament director Stacey Allaster said Williams has had a court constructed at her house with the new US Open hardcourt surface.
However, even with the health protocols put in place, Halep does not intend to compete.
"Given the conditions outlined in the U.S. Open announcement this morning, as of today I do not currently plan to play in NYC," she told Reuters.
The world No 2 added she could reconsider her stand if the situation improved by the entry deadline in mid-July and has informed the United States Tennis Association and the women's WTA Tour of her decision.
"I would like to underline that my decision is not set in stone," she said.