Ollie Watkins has signed a new four-year contract at Brentford, who have confirmed they have agreed a deal for Halil Dervisoglu to join them in January.
Watkins, who has attracted interest from Premier League clubs, is now under contract at Griffin Park until 2023.
And Dervisoglu will join from Dutch Eredivisie side Sparta Rotterdam when the transfer window reopens.
The 19-year-old Turkey youth international scored 11 goals in 36 appearances last season as Sparta were promoted via the play-offs.
Meanwhile, Brentford are also planning to offer Rico Henry a new contract.