Alex Lewington will join Saracens from London Irish ahead of the 2018-19 Aviva Premiership season.
Lewington, 26, is one of the most potent wingers in the Premiership having scored 25 tries in 65 top-flight appearances for the Exiles since joining from Leicester in 2013.
He toured South Africa with England Saxons in 2016 but is yet to feature in a senior squad, and is relishing the opportunity to continue his development with the back-to-back European champions.
"I'm Looking forward to working with the squad and the world class talent that Saracens are lucky enough to have," Lewington told the club's website.
"I'm also looking forward to working with the coaching team, and how they can improve my game."
Lewington stayed with London Irish following the club's relegation from the Premiership in 2016, and helped them secure promotion back to the Premiership at the first time of asking.
"I'm eternally grateful as they gave me the chance to play Premiership rugby," he added.
"I will miss my friends there. But I'm looking forward to building new relationships at Saracens."