Arsenal have signed Charlton Athletic's Finland Under-21 defender Carl Jenkinson for an undisclosed fee.
Jenkinson, 19, came through the Charlton youth ranks and follows Jonjo Shelvey - who joined Liverpool last summer - in making the step up from the Addicks academy to the Premier League.
The teenager, who played for England Under-17s before switching allegiance to Finland - the country of his mother's birth, can play anywhere across the back four.
He only made his debut for Charlton in League Two last December, going on to play nine games in the 2010-11 campaign, but Arsenal have seen enough to invest in the defender.
The Gunners have also tied England youngsters Benik Afobe and Chuks Aneke to long-term deals, along with Dutch youth international midfielder Oguzhan Ozyakup.
Manager Arsene Wenger is expected to add some experience to his first-team squad this summer, with Lille's Ivory Coast forward Gervinho, Bolton defender Gary Cahill and Blackburn centre-back Christopher Samba all reported targets.