Wales centre Jamie Roberts has agreed to join Harlequins after the 2015 Rugby World Cup.
To complete the move, Roberts must first be released by French Top 14 club Racing Metro, where he has a contract until June 2016.
The 28-year-old British and Irish Lion will have rejected the chance of returning to Wales with former team Cardiff Blues, who he left in 2013.
Quins boss Conor O'Shea said in April the signing would be a "big statement".
Had he opted to return to Wales, Blues would have had first refusal on Roberts's services under a Welsh Rugby Union agreement with the nation's four regions.
Gareth Llewellyn, a former Wales and Quins lock, says the Aviva Premiership club can offer Roberts the chance to play at the "highest level".
And legendary Wales full-back JPR Williams said this week that Roberts would be "a fool" to rejoin Blues.