The series will visit the Texas circuit on 19-21 April, the second of two slots which had yet to be confirmed when a provisional calendar was revealed last month.
There will as a result be three US races next season, with COTA joining Indianapolis and Laguna Seca on the MotoGP bill.
Carmelo Ezpeleta, CEO of MOTOGP organiser Dorna, said the new event would further boost the series' stateside profile.
"We are excited to be working with Circuit of The Americas to expand our programming in the United States and bring our series to an exceptional new grand Prix facility in Texas," he said.
"We see tremendous opportunities to market MotoGP and grow its fan-base through this agreement and know Circuit of The Americas is the right promoter to help us achieve that goal."
Circuit president Steve Sexton echoed the sentiment, adding: "We're confident it will be a great addition to our programming and draw tens of thousands of people to Central Texas, creating yet another major event with significant economic impact for our region."
The US is currently represented on the MotoGP grid by Nicky Hayden, Ben Spies and Colin Edwards.
Hayden recently signed a one-year contract extension with Ducati, while Spies confirmed he will switch from Yamaha's works team to Ducati's new satellite operation next year.
Edwards will meanwhile stay with CRT squad Forward Racing for 2013.