The Bees are confident of sealing a deal for the 20-year-old Dutch youth international, who would become the club's first signing under new head coach Keith Andrews.
Milambo, a product of Feyenoord's esteemed academy, impressed last season with his versatility and composure in midfield.
Capable of operating both centrally and in a more advanced role, he was a key figure in the side that secured a third-place finish in the 2024/25 Eredivisie and scored three goals in the UEFA Champions League.
On the international stage, he represented the Netherlands at Under-21 level, featuring prominently in their run to the semi-finals of the European Championships, where they were eliminated by Lee Carsley's England.
Brentford are undergoing significant changes this summer. Long-serving manager Thomas Frank has departed to take over at Tottenham Hotspur, with Andrews stepping up from his role as set-piece coach to assume his first head coach position.
On the player front, club captain Christian Nørgaard is set to join Arsenal in a deal worth an initial 10 million pounds, while influential attacker Bryan Mbeumo is close to finalising a move to Manchester United. Strengthening midfield and attacking depth is seen as a priority.