The top half of the Weary Herakles statue, which was bought by the Boston Museum of Fine Arts in 1982, is to be returned to its native Turkey.
After an ongoing dispute, the MFA will reunite the bust with its lower half at the Antalya Museum later this year.
The announcement is seen as a victory for Turkey which is trying to retrieve artefacts it believes have been looted throughout the years.
It is thought the full statue will return to Boston on a short-term loan.
The top half of the sculpture of weary demigod Hercules was purchased in 1981 from a German dealer, by the MFA and late New York art collecter Leon Levy.
A year later, it was displayed at the US museum before being put into storage in 2007.
Turkish archaeologists were convinced the bust had been looted and taken from the country. At the same time, the lower half of the statue was discovered in 1980 at Perge in southern Turkey.
The MFA always denied that was the case, insisting the bust could have been found "any time since the Italian Renaissance".
Speaking to the Times newspaper, Katherine Getchell from the Boston Museum, said: "It's only in the last couple of years that they've presented us with photos and other evidence of looting from that site."
This is the latest victory for Turkey's campaign to track down lost antiquity.
In May, the Pergamon Museum in Germany agreed to return a Hittite sphinx after the Turkish Culture Minister threatened to ban German archaeologists from digs in the country.
Ertugrul Gunay told the Times that the country plans to "fight in the same way for all our other artefacts".