Patrons attending Wednesday night’s Bar Revue 2011, an annual collection of campy skits and music put on by Montgomery County lawyers, had already been treated to an impression of Sarah Palin that rivaled Tina Fey’s “Saturday Night Live” performances.

Another performer, dressed as Mick Jagger, belted out “Crime Is On My Side,” offering a dead-on mimic of the Rolling Stones frontman singing one of his band’s classics of a similar name.

And two members of the county’s legal community who were once ballet dancers had a mostly funny recurring bit, playing off characters from the movie “Black Swan.”

And then, about an hour into the very long show, the master of ceremonies announced a “new talent” would be performing for the audience of close to 300 in Rockville.

It was at that point that Maryland Gov. Martin O’Malley (D) — the real one — walked on stage carrying an acoustic guitar, sans his suit jacket, with his blue power tie loosened and his sleeves rolled up.

“I don’t know who your organizer is, but she was very persistent,” O’Malley told the crowd in the F. Scott Fitzgerald Theater.

The governor, who fronts the semi-retired Celtic rock band O’Malley’s March, proceeded to offer up two solo numbers that, by his own admission, weren’t exactly well-rehearsed but were nevertheless very well-received, judging by the raucous applause he got.

O’Malley explained that he had come to the venue directly from the airport, where he returned from Chicago, site of an event he attended as chairman of the Democratic Governors Association.

“I have no idea what I’m going to do,” O’Malley said, as he set up his microphone and searched to remember the key of his first song.

He soon had the audience and house orchestra engaged in a call-and-response cover of “Susquehanna Down” by the late folk singer Tom Wisner, who wrote several songs about the Chesapeake Bay.

Next up was another audience-participation number: a cover of Irish singer Luka Bloom’s “Tribe,” which O’Malley also played while attending a reception in March at the Washington residence of Israeli Ambassador Michael Oren. A video of that performance, as O’Malley noted for his Rockville audience, was captured on YouTube.

On the way out, O’Malley noted that his appearance at the Montgomery County Bar Foundation event — which raises money for pro bono clinics and other programs — was a homecoming of sorts. O’Malley grew up in the county, and his late father was a practicing lawyer there.

By 10 p.m., the governor was gone, presumably headed back home for a few hours before a scheduled appearance Thursday morning in Washington with Vice President Joe Biden.