George Stevens Jr., shown at back right at the formal dinner Dec. 6 preceding this year’s Kennedy Center Honors, announced at the celebration that this would be his last year producing the event. (Sarah L. Voisin/The Washington Post)

The carefully orchestrated Kennedy Center Honors went off script Sunday when its longtime producer shocked the audience, including the center’s board of trustees, by announcing that he was being pushed out of his role.

Chairman David Rubenstein had just thanked the crowd for its generosity and thanked producers George Stevens Jr. and his son Michael, a traditional part of the annual celebration. Then Stevens came on stage and personally blamed Rubenstein for forcing him out after 37 years.

“We accept that this will be our last Honors,” Stevens said, as his son stood next to him. “This is our good night.”

The bombshell stunned the audience, which gave Stevens an awkward standing ovation as he left the stage. But his announcement detracted from the remainder of the star-studded fundraiser. Tom Hanks, ballerina Patricia McBride and soul legend Al Green had already been feted, but tributes to Lily Tomlin and Sting were next. The crowd was still reeling from what one longtime supporter called “unnecessary, unseemly, classless” remarks.

“George chose to go out in a blaze of petulance,” said another observer who, like most close to the arts institution, spoke on the condition of anonymity.

George Stevens Jr. arrives for the formal Artist's Dinner honoring the recipients of the 37th Kennedy Center Honors on Dec. 6. (Ron Sachs/Pool/European Pressphoto Agency)

In years past, Stevens and his son were introduced and then waved to the audience from the stage. On Sunday night, Stevens told Rubenstein just minutes before they went on that he planned to speak briefly. It wasn’t entirely spontaneous: Stevens had inserted his coup de grace into the teleprompter. Rubenstein, who was still onstage when Stevens spoke, is “disappointed for George and his family,” a person close to the chairman said.

The announcement may have been a surprise, but the split was a long time coming. This was the last year of a three-year contract between the Kennedy Center and Stevens, 82, and there has been talk for months that it wouldn’t be renewed. Behind the scenes, people familiar with the situation say, the arts center had tried to provide a “graceful exit” for Stevens.

Reached late Monday, Stevens declined to comment further. “I said what I had to say last night,” he said.

For the past few years, the relationship between the Kennedy Center and Stevens had cooled. Officials were not thrilled with the show, which many board members thought had become repetitive and predictable. They wanted changes, but Stevens, whom some describe as prickly, did not want to relinquish any control. But it was also his baby for almost four decades, and he hoped to pass the franchise on to his son.

Another reason: Stevens was paid more than a $1 million a year for producing the annual broadcast, according to several sources.

Months ago, the board established a subcommittee to review extending Stevens’s contract for three more years. The subcommittee and an executive committee recommended against the extension, and Rubenstein also consulted with a number of people close to the institution: “The consensus was it was time to make a change.”

Once the internal decision had been made, Rubenstein began negotiating with Stevens for his departure. Up to a week ago, they were still at odds over the terms, sources said. As one condition for leaving, Stevens wanted his own Kennedy Center Honor next year — or Rubenstein offered it, depending on whom you ask.

Although there have been rumors that CBS, which broadcasts the two-hour program every December, has wanted to update the show, a spokesman for the network expressed its long-term commitment and said it will air the celebration through 2019.

Had Stevens not taken the stage Sunday night, he likely would have received an effusive public send-off, like other departing Kennedy Center officials. “George is a pioneer and innovator,” Rubenstein said Monday. “We are grateful for his 37 years of helping America honor our great performing artists. He has established a remarkable foundation that we will work to build upon going forward.”

The Kennedy Center expressed its gratitude for the contributions that Stevens and his son Michael have made to the Honors over the years, spokesman John Dow said in a statement Monday. “With [Sunday’s] news, the Kennedy Center will begin a search for an Honors producer that will build upon this strong foundation in the years to come.”

roxanne.roberts@washpost.com