Newport Gwent Dragons loose-head prop Owen Evans will join Harlequins at the end of the season.
The 26-year-old, who represented Wales at the 2009 Junior World Championship, joined the Dragons in 2012 and has scored two tries in 62 appearances.
"I feel now is the right time to take the jump to the Premiership," he said.
"I want to develop and with the international props in the squad I feel that Quins can push me further. I can't wait to start pre-season."
Evans, the son of former Wales prop Ricky who won 19 caps between 1993 and 1995, has seen former Leicester veteran Boris Stankovich preferred as first choice at Rodney Parade this season.
Harlequins head coach John Kingston described Evans, who previously played for Llanelli Scarlets, as "a highly motivated and hardworking player".
Kingston added: "He has serious designs on developing his game to reach the very top and we look forward to helping him realise his ambitions."