West Ham have agreed a deal to sign Ajax midfielder Mohammed Kuduso for 44.5m euros(£38m) plus add-ons.
The 23-year-old scored a hat-trick in Ajax's Europa League play-off win over Ludogorets in Bulgaria on Thursday.
The Hammers were represented at the game, with the Ghana international saying afterwards it might have been his last match for the Dutch side.
Kudus is set to fly to London for his medical on Saturday.
He has been the subject of huge interest from Premier League clubs this summer and Ajax have inserted a sell-on fee in the deal.
Brighton were understood to have reached an agreement with Ajax for Kudus earlier this month, but they were unable to finalise personal terms.