Pape Matar Sarr has joined Tottenham from French club Metz.
However, the 18-year-old, who has already won two international caps for Senegal, will remain with the Ligue 1 side for the rest of the season.
The defensive midfielder played 25 times for Metz last season, scoring four times, and has played all three of their games so far this term.
Billed as a signing for the future, Sarr will see out the remainder of the campaign in France before joining up with his new club next season.
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Sarr is the fourth summer signing for Spurs, who have brought in Bryan Gil, Cristian Romero and goalkeeper Pierluigi Gollini as well as Sarr.
Tottenham announced a departure on Friday, with Moussa Sissoko joining Watford after five years at the north London club.
Danny Rose, Erik Lamela and Toby Alderweireld have also left the Tottenham Hotspur Stadium this summer.
Nuno Espirito Santo has confirmed Tanguy Ndombele will not be involved in Spurs' game with Watford as the midfielder continues to be linked with a departure from the club.
The head coach was less forthcoming on whether there will be more additions to his squad before the transfer deadline.
He said: "What we need and what we believe we'll keep is among ourselves.
"I'm so sorry to not answer that question but of course we speak, we see, we analyse and we have to decide and like I say it's not easy to find the right players because we have very good players.
"As long as it is open anything can happen. We have to be aware of the situations of all the team, the window is going to close on Tuesday, until then let's see."
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