The 16-year-old, who has represented Turkey at under-17 level, will officially sign for the Premier League side in January.
Lions boss Kenny Jackett told the club's official website: "We will do everything in our power to keep our best young players.
"However, in a case such as this, it is impossible ultimately to stop a boy leaving when a Premier League club such as Liverpool makes him an offer.
"That being the case, we have secured financial compensation which will enable us to nurture and bring through other promising players for Millwall."
Source: PA
Source: PA