It's not necessarily a shock when a wine server at a winery tasting room leads visitors in a round of "Happy Birthday" on request.

But no one at the Meadowcroft Wines tasting room at Sonoma's Cornerstone complex was expecting the classically trained bass-baritone singing voice of Stephen O'Malley.

Since starting work at the Meadowcroft tasting room last July, the singing wine server has expanded his repertoire to include standards, show tunes and even a little opera. He also has won a following.

"I've heard him sing four or five times in the last few months," said Cynthia Stringer, a member of Meadowcroft's wine club and a frequent visitor to its tasting room.

"I go to a lot of tasting rooms and I really like the fact that Stephen sings, because it adds a nice, homey, elegant feeling," she said. "It's very classy. And I've found that people are friendlier with one another after he sings."

O'Malley, 24, of San Rafael, studied voice at the Catholic University of America in Washington, D.C., for two years before switching to English literature and earning a bachelor's degree at St. Mary's College of California in Moraga.

"I am a trained singer," O'Malley said. "I've been singing for over

10 years."

O'Malley was visiting the Meadowcroft tasting room with friends one day when someone mentioned he could sing, and he was urged to demonstrate.

"I sang one of my old crooner tunes that I like to sing, and pretty soon after that, the tasting room manager called me up and asked me if I wanted a job," O'Malley recalled. "Now I just sing there all the time."

His favorites include "If Ever I Would Leave You" from the Broadway musical "Camelot," Nat King Cole's

"Orange Colored Sky" and Elvis Presley's "It's Now or Never."

O'Malley performs, and pours, at the Meadowcroft tasting room, 23574 Highway 121, Sonoma, from 11 a.m. to 5 p.m. every Thursday through Monday.