The Bhoys are now set to beat the likes of Standard Liege, Racing Genk, rivals Rangers and Aston Villa to his signature.
The Bhoys are now finalising the deal, believed to be worth around ?1million, with the player's club Germinal Beerschot and the transfer could be concluded within 48 hours.
Speaking to skysports.com, the player confirmed that he was ready to make the move to Parkhead.
"I am extremely excited, Celtic is a legendary club," he revealed.
"I am looking forward to this, I have had a great time with GBA, and I look forward to the next chapter of my career at Celtic."
The 20-year-old Kenyan is the brother of Inter Milan star McDonald Mariga, and made his international debut in an unofficial friendly against Nigeria, aged just 15.
Source: Team Talk
Source: Team Talk