Northampton Saints will sign Munster fly-half JJ Hanrahan at the end of the season on an undisclosed contract.
The 22-year-old is in the final year of his deal with the Irish province, where he has played 51 games since his debut in September 2012.
A product of the Munster academy, he has been capped at Ireland schools and Under-20 level.
The Kerry-born stand-off rejected a deal to remain with the two-time Heineken Cup winners.
Hanrahan's appearances at Munster have been restricted in recent months with coach Anthony Foley generally naming Ian Keatley in the number 10 jersey.
|BBC Radio Northampton sports editor Graham McKechnie|
|"Saints have signed Hanrahan on potential. While Bath [Rhys Priestland] and Wasps [Jimmy Gopperth] have both signed experienced fly-halves this week, Hanrahan is a player who's still learning the game. It's a very good signing, but Stephen Myler is still very much their number one fly-half."|
Munster chief executive Garrett Fitzgerald said: "We understand his reasons for leaving and appreciate the opportunity available to him.
"We have done everything possible in looking to retain such a skilful player and offered a highly competitive package, but unfortunately the decision is out of our hands."
Hanrahan will contest the number 10 shirt with England international Stephen Myler at Northampton.
"I have had nothing but positive experiences at Munster," he said. "It is my home club and running out in the red jersey has been and remains a great privilege.
"Like Munster, Northampton is a club that has a proud history, great structures and a passionate supporter base. I am really looking forward to testing myself in a new environment."
Saints director of rugby Jim Mallinder added: "JJ is a tremendous prospect. He has consistently shown that he has the ability to compete at the highest level of club rugby.
"But while we are looking forward to having JJ join us in the summer we are particularly excited about seeing him develop over the coming years at Franklin's Gardens."
Ian Keatley, Hanrahan's rival for the Munster fly-half jersey over the last two seasons, has agreed a two-year contract extension with the Irish province.
Keatley came off the bench in Ireland's 49-7 win over Georgia in November as he edged ahead of Ulster's Paddy Jackson in Joe Schmidt's fly-half reckoning.