Bournemouth have taken full-back Alex Jimenez on loan from AC Milan in an agreement which means they will have to sign the Spaniard on a permanent deal if he makes 18 Premier League starts this season.
If he hits that mark then the Cherries will sign the 20-year-old permanently for £16.5m.
The Spain youth international, who came through Real Madrid's academy, said: "It has always been one of my dreams to play in the Premier League."
Jimenez will provide manager Andoni Iraola with another defensive option following the signings of centre-back Bafode Diakite for £34.6m from Lille, left-back Adrien Truffert from Rennes for £14.4m and goalkeeper Djordje Petrovic for £25m from Chelsea.
Bournemouth have had a busy summer, having lost defenders Illia Zabarnyi, Dean Huijsen and Milos Kerkez for a combined total of about £150m to Paris St-Germain, Real Madrid and Liverpool respectively
The Cherries also sold Dango Ouattara to Brentford for £42.5m and have had a record selling window, with £215m in incoming transfer fees.
Ben Gannon-Doak joined the club from champions Liverpool for £25m earlier in the summer, while Moroccan winger Amine Adli arrived from Bayer Leverkusen for £25.1m.
Also on deadline day, home-grown Cherries midfielder Ben Winterburn, 20, joined League Two side Barnet on a season-long loan.
Bournemouth sit seventh in the Premier League table following a 1-0 win over Spurs on Saturday.
