Saracens have signed Scotland winger Sean Maitland and South Africa prop Vincent Koch.
Maitland, who has won 21 caps for Scotland, joins the Aviva Premiership and European champions from London Irish on a "long-term contract".
Koch, 26, joins from the Stormers on a two-year deal having won two South Africa caps.
"We identified Vincent as a player who could make a significant contribution to the squad at tight-head and he is a player with huge potential," Saracens director of rugby Mark McCall said.
"Sean is a highly experienced and proven international three-quarter, and we believe that he will flourish here.
"Both players are exactly the kind of characters we think will thrive in our environment, and we are confident they will become key players."
Maitland who is currently touring Japan with Vern Cotter's Scotland side, said: "When I was approached about joining Saracens I had no hesitation in accepting the opportunity to join up with their squad.
"The results they have achieved this season speak for themselves but what really appealed was the burning desire from the coaches to continuously improve and evolve. I think the surface at Allianz Park will suit my game and I look forward to meeting up with my new teammates in the summer."