PROVIDENCE — Legendary blues musician B.B. King wasn’t even supposed to speak, let alone sing.

But there he was on the stage, wearing his cap and gown, his newly awarded academic hood draped over his shoulders, facing a sea of graduating Brown University students and their families, all of whom, it seemed, were cheering and clapping.

“I wasn’t supposed to say anything,” said King, 81, after receiving an honorary doctor of music degree during the university’s commencement ceremony on the College Green. “But I got permission.”

“I never tried to do what I’m going to try to do for you, because I think you are the future. You are the ingredients that I think will make the world better.”

He treated the crowd to a slightly improvised, a cappella version of Guess Who, from his 1972 album of the same name, released before most present were born.

“Someone really loves you / Guess who / Guess who / Someone really cares / Guess who / So open your heart / Oh, then surely you’ll see / That the someone (we dedicate this to Brown, too) / Who really loves you / Is me.”

And so went Brown University’s 239th commencement: a mix of traditional procession, Latin admonitions and academic regalia, spiced with a few moments of spontaneity.

There was Jeffrey Thompson, waiting to receive his degree in neuroscience. He was hungry, so he called his girlfriend on his cell phone, and asked her to deliver a pizza to the front row. She agreed and somehow made it past security, to the delight of Thompson and the fellow graduates seated to his immediate right and left.

Joel Howard Willis Weinberger, who was receiving two degrees — a bachelor’s and master’s in computer science — was on his cell phone with two people. His girlfriend, also graduating from Brown but sitting somewhere else, was on hold; his mother was on the other line, trying to find his keys.

The Brown Band played “Pomp and Circumstance,” as well as the theme song from the British claymation movies featuring Wallace and Grommit.

The university awarded 2,194 degrees in total — 1,529 bachelor’s, 359 master’s, 263 professional degrees and 43 honorary degrees.

For most of the graduating students, the day began with the traditional march out of the Van Wickle Gates, on Prospect Street. The largest group — the bachelor degree candidates — walked to the First Baptist Church in America, where they gathered outside for a 10-minute convocation ceremony. For the second year, most of the students remained outside because of the large size of the class. Some representatives of the senior class went inside to bring out the Manning Chair, which is the ceremonial chair used by the president while conferring the baccalaureate degrees.

The graduate students gathered at Lincoln Field, and the medical students at in the First Unitarian Church. The students all reconvened at the College Green, led by commencement chief marshal Richard Canfield Barker, a 1957 graduate and father of two Brown graduates.

The students and their families filled the 12,000 folding chairs arranged on the green, many cheering “07-07.”

Ruth J. Simmons, Brown’s president, presided. Frequently, she used Latin phrases, which sometimes needed translating.

“Baccalaurei in scientiis consurgant,” she said to the bachelor of science candidates, to no response.

Finally she added, “That means stand up.”

The students heard speeches from two graduating classmates: Justin Fabrikant, of Santa Cruz, Calif., and Emily Underwood, of Coloma, Calif., who were selected from 50 applicants to deliver the orations.

“… For every one of our experiences, both glorious and terrible, we have something to show,” Fabrikant said.

“We have grown and adapted, and now, in one way or another, we are prepared for life beyond the warm womb of college. All of us have developed something remarkable and unique to give to the world.”

Underwood described a crushing moment four years ago, while she washed dishes at her hometown café. “I was crying because I had just been informed, without much ceremony, that I was a terrible dishwasher. Unless I could be more efficient, and quit the daydreaming, a more qualified person would be found to take my place.”

Today, she said, she has her “ticket to a future of opportunity” — a Brown diploma.

“The problem is that, although this diploma tells me what I’ve accomplished, I have no clearer vision, today, of what the future holds than I did four years ago, staring into murky dishwater.”

Brown has been a shelter of sorts, much like a grove of aspen trees that provide protection from the lightning storms of Montana that seem to materialize out of the blue, Underwood said.

“An infinite number of small, unremarkable acts have brought us to this celebration. This is our aspen grove. While we are all here, within an arm’s length, let’s decide that we will stay connected. If we can hold our ground, there will be no reason to fear what might come out of the blue.”

tbarmann@projo.com