Britney Spears got an early 27th birthday party in a British nightclub, blowing out the candles on a cake decorated to look like the cover of her new album Circus.

As cameras flashed, Spears was serenaded Saturday in the VIP balcony of the club G-A-Y with "Happy Birthday," another highlight of her European mini-tour in which she's performed her track "Womanizer" on TV shows in Germany, France and Great Britain.

With her comeback on track, Spears is scheduled to return to the United States for an appearance Tuesday – her actual birthday – on Good Morning America.

"The whole year has been a hell of a year for me," she tells Glamour. "I have been working so hard on my album, but I didn't know exactly where I stood with everyone. When I received the awards [at the Video Music Awards] and [the audience] stood for me, it showed me how much love is out there."

Music, she says, has helped her recover.

"Recording this album has helped take my mind off certain things," she tells the magazine. "For me, my music is therapy."