James Malcolm joined the Knights from Glasgow Warriors on loan for the season.
The hooker has made 12 appearances for the Scotland U20's side, while being called up to the senior side for the Six Nations squad this year.
James has played in Scotland his whole career, starting at amateur side Ayr; while being on the Scottish Rugby Elite Development Programme from the summer of 2014 and signed his first professional contract in 2016.
The 23 year-old has featured 25 times for Glasgow Warriors, scoring three tries. One coming on his debut in the European Rugby Champions Cup pool match against the Scarlets, scoring a try in a 43-6 victory.
As part of the deal, James can be recalled by the Scottish club if required during the season.
James scored his first try on his full home debut against Ealing Trailfinders in September.