Martin Braithwaite hitting a ball with a racket: CD Leganes v Real Sociedad - La Liga © Quality Sport Images/GettyImages CD Leganes v Real Sociedad - La Liga

​Barcelona have confirmed the signing of Leganes forward Martin Braithwaite on a four-and-a-half-year deal, after paying the Dane's €18m release clause. 

Following injuries to Ousmane Dembele and Luis Suarez, Barca applied for special dispensation to sign a Spain-based player or free agent outside of the transfer window. 

This was granted by the Spanish Football Federation (RFEF) on Monday and the club moved quickly to activate Braithwaite's €18m release clause, with the signing announced on Thursday morning by Barcelona's ​official website.

The Norwegian, who had top-scored for Leganes this season with eight goals in all competitions, has curiously been given a long-term deal at Camp Nou until the summer of 2024, with a buyout clause set at €300m.

His former club now faces an uphill battle to avoid relegation having already lost another forward, Youssef En-Nesyri to Sevilla last month. Javier Aguirre's side are currently two points adrift of safety in 19th place. 

a man with a football ball on a field: Martin Braithwaite © Soccrates Images/GettyImages Martin Braithwaite

Braithwaite began his career in his native Norway with Esbjerg before moving to Toulouse in 2013. He spent four years in France after which he earned a £9m transfer to Middlesbrough, scoring nine goals in an underwhelming two-season spell at the Riverside Stadium.

He moved to Leganes this summer and will now be playing at Camp Nou for the foreseeable future. 

Braithwaite in is contention for the ​Barcelona squad that take on Eibar on Saturday and he could also make his Champions League debut in just under a week's time when his side travels to the Stadio San Paolo to take on Napoli. 

Leganes meanwhile have confirmed they too will seek special dispensation to sign a replacement outside of the normal transfer window, after being left in a 'situation of enormous damage' according to director Martin Ortega.

He said: "We want to raise our voices. We are in a situation of enormous and serious damage. We cannot understand the current regulation that a club, having a long-term injury can perform this operation unilaterally and transfer its problem to another club.

"We are excited about the possibility that the FA will allow us to sign a player. We will fight to make this possible."