The powerful flanker, who arrives at Sixways later this week, joins from Ealing Trailfinders where he enjoyed a remarkable start to the season with five tries in just six games.
Durutalo also picked up the man-of-the-match award on three occasions and leaves the Greene King IPA Championship outfit in second place in the table – just four points behind Bristol Rugby.
The 29-year-old has 19 international appearances under his belt, crossing the whitewash on four occasions, and represented the USA Eagles at the 2015 Rugby World Cup.
The big back row has also featured for USA’s Sevens side and was part of the squad that took part in the inaugural tournament at the Rio de Janeiro 2016 Olympic Games.
Born in New York City to Fijian parents, Durutalo returned to Fiji as a youngster and went on to captain Fiji’s Under 19 and 21 teams.
He earned a scholarship to attend Hakuah University in Japan and later played Super Rugby for the Sunwolves in Japan for the 2016 season.
Warriors Director of Rugby Gary Gold said: “Andrew is a talented, strong individual who will add some extra firepower to our back row so we’re looking forward to seeing how he goes.”
Durutalo added: “I’m delighted to make the step into the Premiership and can’t wait to show what I can do on the pitch.”