Saints have completed the signing of South Africa scrum-half Cobus Reinach.
The 27-year-old will join the club from Super Rugby side the Sharks, where he has spent his entire career to date.
Reinach has won 10 caps for South Africa and scored against England at Twickenham in 2014.
He becomes Saints' fourth signing ahead of next season, joining Bristol duo Jamal Ford-Robinson and Mitch Eadie, and Australia centre Rob Horne.
Saints have now completed their scrum-half line-up for the 2017/18 campaign, with Reinach joining Nic Groom, Tom Kessell and England Under 20s ace Alex Mitchell at the club.
Lee Dickson is out of contract this summer and looks set to move on.
But the signing of Reinach will be a big boost, and the player is pleased to be switching to Saints.
“I’m delighted and excited to be joining Northampton,” Reinach said.
“It is a club with a long tradition and strong values and I’m really looking forward to playing at Franklin’s Gardens and being in their environment.
“Saints have some outstanding players in their squad and I knew after speaking with the coaches that it was a club that I wanted to play for.
“I want to thank everyone at the Sharks for all they’ve done for me in my career, and I’m 100 per cent committed to them until the end of the season.
"I’m looking forward to the Super Rugby campaign and hopefully finishing on a high note with the Sharks and regaining my place in the Springboks’ squad.”
Saints will now continue their bid to strengthen at fly-half, having missed out in their attempts to sign Aaron Cruden, George Ford, Dan Biggar and Pat Lambie, whose move was blocked by South Africa.
The club have now moved on to fresh targets and remain bullish about getting a big name in to supplement Stephen Myler next season.
Boss Jim Mallinder is delighted to have snapped up Reinach, having had his eye on the player for many months.
“Cobus is an excellent player and we’re looking forward to having him at Franklin’s Gardens next season,” Mallinder said.
“We have been watching him for some time and he has proven time and again what a quality player he is. His set piece skills are excellent and he is a very opportunistic scrum half.
“We need quality players in each position to be able to compete at the highest level and Cobus further enhances a position where we are already strong with Nic Groom, Tom Kessell and Alex Mitchell.”