Scotland winger Sean Lamont has put pen to paper on a three-year deal with the Scarlets.
The Perth-born star had been in talks with French club Brive but those broke down and he has opted instead to join the Welsh outfit.
Lamont joined Northampton from Glasgow in 2005 and scored 23 tries in 68 appearances for the club.
The powerful winger has 37 caps for his country, the last of which came in the RBS 6 Nations opener against Wales at Murrayfield in February.
He will join Nigel Davies’ squad for pre-season training in July with no Scotland summer tour this year.
He said: “I’m thrilled to be joining the Scarlets. They’re building an exciting squad and are based at one of the finest rugby facilities I’ve ever seen.
“There’s great passion for the sport in Wales especially across the Scarlets region so I can’t wait to get going and join up with a great group of players and such a well-known rugby club with proud traditions.”