Middlesbrough have completed the signing of Julien De Sart from Standard Liege on a three-and-a-half-year deal.
The 21-year-old joins the Championship high-flyers for an undisclosed fee having risen through the ranks at Standard Liege and gone on to make 66 appearances for the club.
De Sart, who plays as a defensive midfielder, has represented Belgium at every level from Under-16s to Under-21s, but is yet to receive a senior call-up for his country.
He will now join Boro's bid for promotion to the Premier League and could make his debut against Blackburn Rovers this weekend.
De Sart becomes Middlesbrough's third signing of deadline day following the arrivals of Jordan Rhodes and Ritchie De Laet.
