The 19-year-old is highly rated and helped Genk to win the Belgian championship last season.
Chelsea have been tracking him for a number of months and, despite reported interest from Atletico Madrid, a deal looks set to be concluded.
Courtois' father and agent Thierry confirmed a deal was close and he expects it to go through on Tuesday.
"He [Thibault] was in Chelsea last week," he revealed to Het Belang Van Limberg.
"I think Chelsea and Genk have reached an agreement. Tuesday we will come and talk about the transfer."
Chelsea are reportedly happy to let Courtois return to Genk on loan, and his father admitted this was an option but he rubbished any claims he could sign a new deal with the Belgian club.
"Maybe Chelsea will lend Thibaut to Genk, but a contract extension does not interest us anymore," he added.
Chelsea are still understood to be keen on making a double swoop on Genk, as talks over midfielder Kevin de Bruyne also continue.
The Blues had hoped to send De Bruyne back on loan to Belgium, but to Genk's rivals Anderlecht, which would also have helped their continued pursuit of Romelu Lukaku.
However, Genk have insisted they will not allow De Bruyne to be loaned to any other Belgian club should he be sold.
Regarding Lukaku, he admits he is more than happy to stay at Anderlecht, should his move to Chelsea fail to materialise.
"Occasionally you might yearn for something new, but for now I sit here very well. We'll see where it goes," he said after returning for pre-season training, where he was joined in the first team by his young brother Jordan.
But he still admits a move to England is his dream, adding: "I would really like a top transfer and I have always wanted to go to England."
Source: Team Talk
Source: Team Talk