South African forward Gerrit-Jan van Velze will move to Worcester from Northampton this summer.
The 25-year-old No 8, who is currently in his second campaign with Saints, has decided to make the switch to Sixways ahead of the 2014/15 season.
"It is fantastic that GJ has decided to join us," said Worcester rugby director Dean Ryan.
"He is an experienced Premiership player with strong leadership qualities who we see being influential on the pitch as well as joining a strong leadership group to help us build a new culture here at Worcester."
Van Velze said: "I had a conversation with Dean Ryan, during which he explained the challenge ahead.
"It's a different challenge to the one I've had at Northampton but it's something I'm looking forward to."
Worcester have also announced that Rotherham scrum-half Charlie Mulchrone, Ospreys prop Joe Rees and Plymouth Albion centre Heath Stevens will join them at the end of this season.
Mulchrone, 24, has already demonstrated his leadership abilities through his captaincy of Rotherham Titans this season, and also plays at fly-half.
Tighthead Rees has made 30 appearances for the Ospreys and has played for Wales at U18 and U20 level.
Stevens, 24, has appeared in all 13 Championship games for Plymouth Albion this season.