Clark will head for Franklin's Gardens at the end of the season
Leeds Carnegie forward Calum Clark has signed for Northampton Saints and will head to Franklin's Gardens this summer.
Clark, 20, specialises at open-side flanker but is able to play in all three back-row positions.
He captained England in last year's Junior World Championship in Japan, leading the side to the final.
"It's going to be a real fight for me to get into the [Northampton] squad - I'm under no illusions about that," said Clark.
"I'll have to get my head down and graft, and then make the most of my opportunities if I get them.
"There are some quality players at Northampton and hopefully being around them will improve my own game.
"I also know how passionate the fans are from playing there, and I'm looking forward to joining the Saints," he added.
Clark made his debut for Leeds against Saracens in September 2007 after coming through the club's academy system.
I'm fully committed to Leeds until the end of the season and am desperate to go out on a high
And he admitted it was a tough call to move on.
"It was a really hard decision to make and my leaving isn't a negative reflection on Leeds as a club," Clark explained.
"I've grown up there and it will always be close to my heart. But I've made a decision to push on and make the best of myself, and Northampton was an impossible club to say 'no' to.
"But I'm fully committed to Leeds until the end of the season and am desperate to go out on a high."
Saints director of rugby Jim Mallinder is delighted with the signing.
"Calum has made an excellent start to his career and we're excited that he'll be part of our squad next season," he said.
"He's rightly regarded as one of the brightest prospects in the country with good ball-handling skills, physicality and a mature approach to the game.
"We understand there was a lot of interest from other clubs and I'm delighted that Calum has confidence in where we're taking the club."