Douglas has made 43 appearances for Scotland where his 5ft 11in, 17st 5lb has made a name for himself as a strong scrummager.

He was in the Border Reivers side which was axed by the Scottish Rugby Union at the end of last season and he will go head to head with fellow new signing Ben Broster to earn the Scarlets No.3 shirt for the next campaign.

Scarlets Chief Executive Stuart Gallacher said: “We are delighted to welcome Bruce to the Scarlets. He will bring plenty of experience to the side and I’m sure he will welcome the challenge of earning a starting place in the side.”