London Welsh have signed former Scarlets number eight Chris Hala'ufia and fellow Tonga forward Opeti Fonua.
Hala'ufia joined the Exiles last month on a two-week loan basis.
The 36-year-old, who previously played for Harlequins, has made two appearances for Welsh and 107 in the Premiership overall, scoring 12 tries.
"He's got the experience and he's also got that physicality we want - he's able to get over that gain line," said London Welsh head coach Justin Burnell.
"Chris impressed me with his performance against Newcastle, but he also impressed me on and off the training pitch during the two weeks he was with us.
"His attitude was excellent; he was very respectful of the environment at London Welsh and he got his head down and worked hard."
Capped 24 times by Tonga between 2000-2009, Hala'ufia has scored five international tries.
Fonua, 28, has played five times for Tonga and joins the Exiles from French Top 14 side Bayonne.
He is also a number eight, stands 6ft 6ins tall and weighs 134 kgs (21 stone) and Burnell said: "Gain line supremacy is a massive aspect of the game in the Premiership and when you look at the size and physicality of Fonua, it's phenomenal."