The Portugal international has joined the Dutch Eredivisie club from German Bundesliga side RB Leipzig.
Bruma, 24, was born in Guinea-Bissau, but represents his adopted nation at national level having also played for Portugal at seven different youth categories before making his first team debut two years ago.
The skilful winger came through the ranks at Sporting Club de Portugal before spells in Turkey, Spain and eventually Germany.
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He scored three and assisted the same amount of goals in 27 appearances across all competitions for Leipzig last season.
Bruma is the club's third signing of the transfer window following the arrival of Ibrahim Afellay and Robbin Ruiter.