If you haven't jumped on board yet, don't worry, there's still room: Nikka Costa's bandwagon should be fuller, considering she's been around for years. The 29-year-old singer -- who appears at the Bluebird Theater on Tuesday, July 31 -- opened for the Police when she was only eight and is a multi-platinum-selling artist in Europe. But she's still just breaking in here, and her dance card is rapidly filling up. Much like a female Lenny Kravitz in terms of pedigree, sexiness and urban appeal, Costa has a bio that reads like a who's who in twentieth-century icons. Her father, Don Costa, produced names like Paul Anka, Tony Bennett and Frank Sinatra (Ol' Blue Eyes was her godfather), and she grew up playing at the feet of people like Quincy Jones and Sammy Davis Jr. Turns out, she paid lots of attention. Her sound is wholly unique, an amalgam of folk and contemporary R&B, soul and rock. Her vocal command is startling -- blues edged and gravel lined one minute and silky smooth the next. She's still touring behind Everybody Got Their Something, which has tunes featured on both the Blow soundtrack and a Tommy Hilfiger commercial. The compositions are drenched in groove and seriously danceable, yet beset by smart melodies and ultra-hip phrasing. Long story short: Nikka Costa is a comet, and we should all be reaching for that tail.