Roberts is poised to join his international colleagues Mike Phillips, James Hook, Gethin Jenkins and Luke Charteris in France next season after rejecting a new deal from Cardiff Blues.
Although Roberts' destination next term has yet to be announced, it is understood it will be wealthy Parisians Racing Metro, whose most recent signing was former Bath and England back Olly Barkley.
The Welsh Rugby Union tonight issued a statement on 26-year-old Roberts' behalf ahead of his return to Test rugby against Argentina this weekend after recovering from knee surgery.
And Roberts has already been reminded of the need to secure release for key Wales training camps when he starts a lucrative club career across the English Channel.
The current France-based quartet missed Wales' critical pre-autumn training stint in Poland last week due to club commitments.
While Toulon prop Jenkins still starts against Argentina on Saturday, Phillips and Hook are on the bench and Charteris plays for Perpignan this weekend after a deal was struck between his club and Welsh Rugby Union that would see him freed in return to face Australia on December 1.
Roberts said: "I am proud of what I have achieved so far in my rugby playing career and remain determined to continue to aspire to win international honours for Wales.
"This has been an extremely difficult decision, but I am absolutely certain it is the correct time for me to enter a new stage of my career.
"My intention is to emerge from the experience of playing for a new team as a better rugby player and to broaden my personal horizons in a new environment.
"I owe a great deal to Wales and to Welsh rugby, and I retain today the pride I felt in 2008 when I first pulled on the international jersey for my country of birth.
"As professional players we work immensely hard, and there comes a time when you know that a fresh environment will help you retain the sharp edge of determination required to remain a contender for top honours.
"I have enjoyed an incredible time at Cardiff Blues in the company of some great players, coaches, administrators and fans who have helped shape my career."
Roberts is currently in the final academic year of studies to become a doctor, and he added: "I will complete my medical training in March, and I currently have the opportunity to step outside the academic environment for a couple of years before I take up my required hospital training period."
His pending move away from Wales, though, provides the national team coaching set-up with another potential hurdle to overcome in terms of player release before and during Test match periods.
"It is obviously a difficult scenario for us," Wales skills coach Neil Jenkins said.
"We want our best players playing in Wales as often as possible.
"Jamie has made a decision that he won't be with the Blues. The most important thing from our point of view is that whenever he does go, he gets full release and he can come to these pre-autumn and pre-Six Nations training camps.
"If that is the case, Jamie will be a full part of this Wales squad going forward.
"He is an outstanding player. He has been outstanding for Wales and the British and Irish Lions. He leads from the front."
Blues chairman Peter Thomas, meanwhile, has issued a stark warning that Welsh rugby's exodus of top players will continue without increased funding.
The Blues have claimed that 44 times-capped Roberts turned down a deal with them that would have made him among the United Kingdom's highest-paid players.
Wales interim head coach Rob Howley has already delivered a blunt message about players' international prospects if they opt to move outside the Principality.
Thomas said: "We have invested a lot of time, money and effort developing Jamie as a rugby player from an early age after identifying him as a star of the future.
"We have stuck by him through thick and thin and supported him during last season when he only completed two matches for the Blues because of his knee injury and international duties, playing 15 matches for Wales.
"It is impossible for the Welsh regions to compete with the kind of money that is on offer from other clubs in other countries.
"The time has come that the Welsh benefactors should not be responsible for funding the professional game.
"The chairman of the regions can guide companies, but if we want to keep Jamie Roberts and other international players in Wales then the governing body has to intervene.
"The player drain out of Wales, which has a negative impact on the Welsh regions and the national team, will only continue without increased funding from the governing body."
One way forward might be for the WRU to secure top players on central contracts, but WRU group chief executive Roger Lewis recently claimed that Wales' four professional regions - the Blues, Ospreys, Scarlets and Newport Gwent Dragons - rejected that idea.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.