Jonathan Fisher has rejoined London Irish after spending the last year playing for Bedford Blues.
The versatile 23-year-old, who can play at lock, flanker or number eight, has signed a two-year contract at the Madejski Stadium.
He made his initial debut for the club in an Anglo-Welsh Cup tie against the Ospreys in November 2007 and went on to make 19 appearances.
"I am thrilled to be joining London Irish again," said Fisher.
"The club has played a huge role in my rugby development over the last seven years and I want to return and repay that faith."
Fisher represented England in the Under-19 World Championships in 2007 and went on to secure a starting spot at blind-side flanker for the Under-20 side in all five games of the Six Nations Grand Slam campaign the following year.
He also played for England Sevens at the 2008 Hong Kong Sevens and for England Saxons.
"Jon is a player I have worked with before and he possesses a huge amount of potential which has been on show throughout the last season at Bedford Blues," said London Irish director of rugby Brian Smith.
"He deserves the chance to be back and I know he will continue to work as hard as ever."