“The Kennedy Center Honors” writer-producer George Stevens Jr. enjoys springing surprises on the audience — as in this year’s “Proud Mary” performance by Beyonce, complete with Tina Turner-style jiggling body. “We don’t tell anybody what we’re doing. We don’t publicize it. We don’t give a program out, so people don’t know who is going to appear on the stage and they can feel that rush of excitement,” notes Stevens, who has been godfathering the annual rite for 28 years. Washington is a city terribly good at keeping secrets. I think if Bob Woodward had put himself to it, he would have discovered Beyonce was going to be on the show,” Stevens adds with a laugh. “But he wouldn’t have told anyone.”