The crowd at the Oakland Arena probably thought it had paid only to see the Artist Formerly Known as Prince on Jan. 22 but it did a double take when Monterey look-alike, Sir JAC, walked in before the Purple One''s set at 9:30pm.

Dressed in skintight black and a long, white coat, Sir JAC hammed it up from his seat after walking across the floor section and realizing everyone was staring and cheering. In retrospect, he says he was shocked by the reaction. "People were rushing up to me, grabbing my clothes. It was making me, and security, a little nervous."

On Valentine''s Day at Whitey''s Place, you can see Sir JAC do his thing with Live Essence, his tribute to the prolific Prince. In celebration of the Artist''s third wedding anniversary, Sir JAC is planning some romantic surprises. The show will differ from the regular funk-fest only in tone, opening with sweeter ballads, such as "Adore," "The Most Beautiful Girl in the World," and "Do Me Baby."

"I invite everyone who hasn''t seen the show yet to come down," says Sir JAC. "I want people involved, dancing. I create some quality entertainment, a full show where people don''t just come to hear music but they say ''Wow, I''ve just been entertained.''" It doesn''t hurt that Sir JAC bears an uncanny resemblance to the Artist, especially in costume. Last November, he won a look-alike contest in San Francisco, sponsored by the fan group BayNPG.

Rumors that surfaced several weeks ago about the band''s breakup leave Sir JAC shaking his head. "We worked out our differences and we''re still together. Lots of people have worked with Live Essence since it started and some are doing their own things now too." The group currently consists of Geoffrey Lewis on keyboards, Paul Hunt on rhythm guitar and Renzo on lead, two sexy dancers Katt and Barbarella, Jerry Rhen on drums, Matt Puentes on bass and JoanMarie on backing vocals.

The influences on the band range much farther than just the Artist. Lewis, one of the original members, has been learning keyboards and percussion for 10 years, playing reggae and digging Babyface and Depeche Mode. Hunt, who joined the band in August, trained primarily in jazz for 12 years and played in a church in Washington, DC. "Prince brought out the funk," says Hunt. "I saw the Purple Rain tour and I said, ''Man, I gotta learn to play guitar.''"

The idea for a Prince tribute band came to Sir JAC out of a life-long admiration for the musician, who has composed in almost every style imaginable. "They weren''t playing his music here and I missed hearing him. I felt like people needed to listen because he''s done so much for music. In high school, I listened to hard rock. In the military, I got into R&B, and at night I relax to classical, but it all comes back to him."

Besides acting as the royal twin onstage, Sir JAC writes original music in his home studio, works on producing local groups and is honing his piano skills. "Someday soon, I want to play instruments onstage, especially piano like he does. With the fast-paced show now, it might be too much. But I have too much energy to keep me grounded."

Sir JAC and Live Essence, Sat., 9:30 pm. Whitey''s Place, Pacific Grove, $5 advance, $6 door. 646-8383. cw