Kevin Hart is set to step into a boxing ring with poker champ Antonio Esfandiari in March ... and there will be legit money on the line in the fight -- Antonio tells TMZ Sports.
First ... some backstory. Hart and Esfandiari have been solid friends for years -- having played in poker tournaments together every now and then.
Sooo ... when we got the 39-year-old card player leaving M Cafe and he liked the fact that our photog recognized him ... he gave us "some juice" on his friendship with the comedy icon.