Terrell Owens is gettin' the cold shoulder from Ice Cube ... 'cause the ex-NFL superstar's plea to join the Big3 has been officially shut down by the league's founding father himself.
ICYMI -- We talked to T.O. last week about wanting to join ex-NBA hoopers like Allen Iverson, Chauncey Billups and Ricky Davis in Cube's new 3-on-3 league ... and he said he was 100% serious about joining in on the fun.
But Cube was quick to shut down the idea ... telling TMZ Sports T.O. ain't exempt from Rule #1 of the Big 3 -- ex-NBA players ONLY!!
So it looks like it's back to the celebrity games and the Drew League for T.O.'s hoop dreams.