Finn Russell will leave Glasgow Warriors at the end of the season to take up what the club described as a "once-in-a-lifetime opportunity".
The Scotland fly-half has spent his entire senior career with the Warriors and was a Pro12 winner under Gregor Townsend in 2015.
Russell, who earned his 31st Scotland cap against New Zealand on Saturday, says his decision came from a desire to try something new, with the club announcing his departure in a lengthy statement.
Speaking to the Warriors' official website, he said: "I've shared so many fantastic moments with people who are now friends for life and to do it in front of the amazing Glasgow Warriors supporters at Scotstoun has been a dream come true.
"I've always wanted to experience as much as I can during what is a short rugby career. It was obviously a difficult decision to leave Glasgow, but I have the opportunity to take myself out of my comfort zone and experience a new culture and type of rugby.
"However, I am fully focused on Glasgow Warriors and will do everything I can to make my final season at Scotstoun a successful one."
Russell has been linked with a move to Top 14 side Racing 92, and Warriors managing director Nathan Bombrys admitted the number 10 has accepted a "lucrative" offer.
"Our club has an excellent track record of retaining our key players in recent years. However, in this instance Finn has decided to move on and accept a lucrative opportunity at another club," he said.
"We respect his decision and when the time comes we will thank him for his contribution to the club. It has been great watching him develop and grow wearing a Glasgow Warriors shirt.
"We know he will be fully focused on trying to bring another trophy to Glasgow Warriors this season."
|Cavani hails ´good reaction´ as PSG bounce back in style|
|Thiem breezes past Monfils to set up Bedene showdown|
|Mourinho wants referees to have final say on VAR|
|Genoa 2 Inter 0: Pandev piles misery on old employers|
|Manchester United to host Brighton in FA Cup quarter-finals|
|Leinster see off Scarlets as Munster come up short in Cardiff|
|New No.1 Federer earns gritty Seppi win to book Rotterdam final|
|Mata ´still up for VAR´ despite disallowed goal at Huddersfield|
|Valverde: Barcelona had to suffer at Eibar|
|Championship Review: Fulham end Villa run, Cardiff pounce|
|Resilient Kvitova ousts Wozniacki in Doha thriller|
|Huddersfield Town 0 Manchester United 2: Lukaku sends visitors through after VAR controversy|
|Toomua inspires Tigers win over Quins, Worcester beat Gloucester|
|Bayern Munich boss Heynckes hails game-changing Muller|
|Locadia benefiting from ´competitive´ Brighton - Hughton|
|Baby on board? Alba dedicates Barca goal to girlfriend|
|West Brom future ´not a decision for me´, says Pardew|
|Lions get De Bruin off to winning start|
|Paris Saint-Germain 5 Strasbourg 2: Cavani at the double in bounce-back win|
|Bar-celona! Messi posts unwanted record|
|Barca go 31 LaLiga games unbeaten to tie club record|
|Mourinho: I don´t know and I don´t care when Pogba returns|
|Brighton and Hove Albion 3 Coventry City 1: Locadia, Ulloa lead Seagulls to quarter-finals|
|EIbar 0 Barcelona 2: Suarez and Alba seal points as Orellana sees red|
|West Brom 1 Southampton 2: Rondon stunner in vain as Baggies drop out|
|Wolfsburg 1 Bayern Munich 2: Lewandowski spot-on after Robben´s penalty miss|
|I hope Cutrone finds a beautiful girlfriend so he can rest and make love - Gattuso|
|Wellens claims Ruta del Sol lead, Froome suffers puncture|
|Goffin forced to retire in Rotterdam following freak eye injury|
|Allegri denies Champions League ´obsession´ ahead of Turin derby|
|Barry, Evans start for West Brom after training camp incident|
|Bottas unaffected by ´Halo´ on simulation runs|
|Sheffield Wednesday 0 Swansea City 0: Carvalhal settles for replay on Hillsborough return|
|Management ´tiring´ but Zidane not ready to leave Madrid just yet|
|Thiago back for Bayern as Heynckes rests stars for Besiktas|
|Simeone urges Atletico fans to get behind Griezmann|
|Robben amazed by Guardiola´s impact at Manchester City|
|Three-way tie for lead in Oman as Pavon falls away|
|McIlroy frustrated by added scrutiny of playing with Woods|
|Morgan to take it slow with Stokes and backs Rashid|
|Pogba out of Man Utd´s Huddersfield trip with illness|
|A-League Review: Perth ´Panenka´ punished, 10-man Adelaide rescue late draw|
|Dragons and Rabbitohs see off Super League opponents|
|Robben targets two more years at the ´highest level´|
|Rashford and Herrera ´have a chance´ of making Sevilla trip|
|Mixed feelings for Tiger Woods after missed cut at Riviera|
|Emery defends PSG star Neymar after Madrid display|
|Nishikori stays hot in New York as Anderson awaits|
|Kevin Durant: Laura Ingraham´s ignorant comment was racist|
|Thiem sets up Monfils semi-final showdown|
|Mahrez saga now over, says Leicester boss Puel|
|Cantlay, McDowell and Saunders top at Riviera as Woods makes early exit|
|Tiger Woods misses cut at Genesis Open|
|Astros manager Hinch on Cole: He doesn´t need to be fixed|
|Alonso to return for Barca clash but Bakayoko set to miss first leg – Conte|
|Mourinho: Manchester United will sign a midfielder|
|Record-breaking Federer rises back to summit, Goffin to meet Dimitrov|
|Kobe Bryant says Lakers ´shouldn´t need´ to recruit free agents|
|Federer pokes fun at himself after becoming oldest world number one|
|Woods to play Honda Classic as comeback continues|
|Glasgow Warriors book finals berth as Zebre upset Connacht|
|Conte given selection headache ahead of Barcelona clash|
|Atkins at the double as Warrington see off Widnes|
|Giroud ´relieved´ to get first Chelsea goal|
|Sarries scrap for Sale success|
|Records tumble in Federer´s latest remarkable ascent to the top|
|Chelsea 4 Hull City 0: Giroud scores and Willian stars as Blues reach last eight|
|Leicester City 1 Sheffield United 0: Vardy header secures quarter-final spot|
|Agassi congratulates Federer after losing rankings record|
|Kvitova to face Wozniacki after Goerges pulls out|