Wales boss Wayne Pivac believes Dan Biggar and Chris Boyd are the perfect match.
Biggar has been in brilliant form since moving to Saints to be part of the Boyd revolution in the summer of 2018.
The 30-year-old has taken his already strong fly-half game to new levels at Franklin's Gardens, steering Saints to second in the Premiership and into a Champions Cup quarter-final.
And ahead of Wales' Six Nations opener against Italy this weekend, Pivac said: “I think marrying up with Chris Boyd has been fantastic for Dan's game.
“The way Northampton want to play and the way he is playing, I think he’s adding another dimension to his game, which is fantastic for us.
“Dan is a quality player. He brings all that experience. You saw what he did at the World Cup.
“I think it’s going to extend his career with what he is doing at Northampton, so it’s a positive for him.”
It is not only Pivac who has seen a new side to Biggar since he swapped Ospreys for Saints a year and a half ago.
Wales captain Alun Wyn Jones said: “The air he has got, the way he is carrying himself, you can see he’s someone who’s playing away from Wales and playing in a different group.
“He’s even more assured than he usually is and a confident Dan Biggar is a very dangerous player.
“That experience he has had at Northampton, the players around him, is obviously invaluable to him, as he is going to be invaluable to the squad moving forward.”