Soul music legend James Brown was told he urgently needed surgery for prostate cancer two months ago, but the “Hardest-Working Man in Show Business” told his docs: “The show must go on!” — and went out on a grueling concert tour.

He postponed the operation and scheduled it for December 15, a source close to Brown told The ENQUIRER.

” ‘I’ll be in and out in a day,’ he laughed.”

Brown, 71, who also battles serious diabetes, performed shows in Belgium and Canada in October, November and December as he battled the pain and faced the surgery.

He was due back at his Beech Island, S.C., home the weekend of December 11, four days before he was scheduled to go under the knife in Atlanta.

“James was first diagnosed with prostate cancer over a year ago,” an insider disclosed. “He was treated with chemotherapy and the cancer went into remission.

“He thought he’d beaten it. But when he had a checkup in early October the doctors told him it had come back with a vengeance.”

Said the close source: “The doctors told him this was serious. They wanted to operate right away. But James said he had to fulfill his commitments first. ‘I got a promise to my fans to keep,’ he snapped.

“And those fans had no idea of the pain behind his mask of laughter as they watched him strut his stuff onstage. He’s a brave man.” James’ 35- year-old wife and back-up singer Tomi Rae also went on tour with him.

As The ENQUIRER revealed, their stormy marriage appeared to be in jeopardy 18 months ago after reports she had never divorced her previous husband and the James Brown marriage was not legal.

“They’ve never resolved that issue,” said the source. “But they’re back living together as man and wife. They love each other. They fight. But they always kiss and make up.”