ONCE was just not enough and this time “Celebrity Boxing” is gunning for “Friends.”

Fox will air an encore presentation of the campy boxing special, which pitted washed-up TV stars and tabloid trash against each other in the ring, this Thursday at 8 p.m.

The ultra-competitive time slot will pit the second-run boxing special up against a repeat of “Friends,” the highest rated show on television.

The all-star slug-fest – which pitted ‘‘Partridge Family” buffoon Danny Bonaduce against “Brady Bunch” dud Barry Williams, “Diff’rent Strokes” star Todd Bridges against Vanilla Ice and scandal-ridden skate-queen Tonya Harding against Clinton sexgate siren Paula Jones – was seen by about 15.5 million viewers last Wednesday.

Wednesday night’s boxing special was headlined by Harding’s defeat of Paula Jones and its ratings were so good, they even beat a repeat episode of “West Wing.”

Fox sources say plans are already underway for a new “Celebrity Boxing” special that could air as early as May. Grade Z-level media personalities like “Who Wants to Marry a Multimillionaire” bride Darva Conger and Long Island’s own Joey Buttofuoco are already pushing to be part of the next edition.