The deal for the Rubin Kazan winger is likely to be completed in the next 24 hours, and will see the player move to Celtic Park on a season-long loan.
Celtic have been busy in the last week strengthening their squad, adding Manchester City's Jason Denayer and Aleksandar Tonev from Aston Villa in season-long loan deals.
Mubarak is a Ghana international who has won 19 caps for his country, scoring seven times.
He played for Ghana against Germany and Portugal at the World Cup finals in Brazil during the summer.
The 22-year-old played for in Spain for both Villarreal and Espanyol prior to his move to Russia last year.