Albion have signed Dutch defensive midfielder Danny Holla on a three-year contract.
Holla, 26, watched the Seagulls' 1-0 defeat at Birmingham yesterday before completing a medical and putting pen to paper last night.
He has linked up with the squad at St George's Park, where they are based ahead of Tuesday's visit to Leeds.
Holla began his career at FC Groningen in the youth set-up and spent six years with them as a pro.
He also had loan spells with FC Zwolle and VV-Venlo before moving to Den Haag two years ago but has been without a club since the end of last season after 39 goals in 212 career appearances.
Albion manager Sami Hyypia said: "Danny is a player who has plenty of top-flight experience in Holland with more than 200 senior appearances, and that experience is something we need.
"He is a deep-lying midfielder and the scouting reports I have seen on him show he likes to get on the ball, pass it and dictate the play – and I hope he can bring that to the team.
"He's not been with a club during pre-season, so will we need to assess where is in terms of his match fitness, but hopefully we can get him up to speed and ready to go."
Holla is Albion's sixth signing of the summer, joining fellow defensive midfielder Nzuzi Toko, centre-half Aaron Hughes, goalkeeper David Stockdale, striker Chris O'Grady and attacking midfielder Joao Teixeira, who made his debut as a second half substitute at Birmingham on a season-long loan from Liverpool.