Cher is furious at Oprah Winfrey for ambushing her on the talk show with an emotional film clip from Sonny’s funeral — causing her to break down in tears and flee the set.

Without warning or prior discussion with Cher, Oprah showed a clip of the eulogy Cher delivered at Sonny’s funeral in 1998.

Viewers who watched the May 3 show saw a visibly shaken Cher tear up and struggle to continue the interview. But they did not see the distraught entertainer rush off the stage to compose herself and reapply her makeup during intermission.

“Cher had never seen the footage of herself at Sonny’s funeral and had no idea Oprah was going to run it,” revealed an insider.

“It was very emotional for Cher to be transported back to that time. She was totally caught off guard — and it upset her.

“Cher had a right to be angry. For this eulogy tape to come out of the blue like it did was unforgivable on Oprah’s part.”

Oprah regrets surprising Cher with the footage.

Said an Oprah representative: “The footage was part of a tribute to Cher’s legacy and was never intended to upset her.”

And a spokeswoman for the singer told The ENQUIRER, “Cher and Oprah love each other and are very good friends. There is no problem between them.”

But the insider insists Cher feels bushwhacked and is still smarting.

Her ex-hubby Sonny died at 62 in a skiing accident at Lake Tahoe, Calif. The 56-year-old singer, who still had strong emotional ties to the man who made her a star, was devastated.

The Oscar-winning performer agonized for days over whether to allow the taped breakdown to be aired, The ENQUIRER has learned.

“In the end, she agreed because she felt it showed her human side,” disclosed the insider.

“Even though she’s a superstar, she’s still a woman with a vulnerability for those she loves.”