Harlequins prop Seb Adeniran-Olule has died at the age of 20 in a road traffic collision.
The club say they are "deeply saddened" by the death of the England Under-20 international, who had been at the club since the age of 13.
"Our thoughts and prayers are with Seb's family and friends at this difficult time," Quins director of rugby Conor O'Shea said.
"He will be sorely missed by the whole squad as well as by the wider club."
Adeniran-Olule, who played three first-team games for Harlequins, represented England at Under-16, Under-18 and Under-20 level.
He made four appearances at the Under-20 World Cup in Italy last year, where England finished runners-up to New Zealand.
O'Shea described the former Whitgift and Wellington College pupil as an "incredible talent", while John Fletcher of the Rugby Football Union said the front-row forward was an "absolute pleasure to be around".
"He was one of the most skilful players in his position I have ever seen," Fletcher, the national academy development manager, told the RFU website.
"He always played the game with a big smile on his face and could do some phenomenal things with the ball.
"As a character he was quiet, had incredible work rate, was popular and first to learn. On the pitch he would get you off your seat and as a front-row player that is fairly rare.
"He should be remembered as a great kid, I loved coaching him. It's a tragic loss."