She’s got a Circus theme for her album, her tour, her “Good Morning America” appearance and even her birthday party.

For her 27th birthday bash in New York on Tuesday night, Britney Spears turned nightclub Tenjune into a three-ring circus. Brit showed up in a low-cut Roberto Cavalli cocktail dress, with her hair done up loosely. The party was attended by her mom, Lynne, as well as celebrities like Ciara, Lance Bass and Jeremy Piven.

(Check out photos of Britney from inside the party.)

The party was featured jugglers, a man on stilts and carnival concessions like hot dogs and popcorn, according to UsMagazine.com. Outside, circus images were projected onto a screen.

Spears told “Entertainment Tonight” her simple birthday wish: “A million more wishes!”

“I’ve definitely known her for a long time and it’s been amazing to see the career she’s had,” Lance Bass told “ET” outside the party. “It’s going to be an amazing career for her. It’s great when people do themes to their albums.”

Fellow partygoer Ciara was also excited to spend Britney’s big day with her, and was hesitant to label Circus a comeback record. “I was actually watching her interview the other day where she said she doesn’t like the word ‘comeback,’ so I won’t say that,” she told ET. “But, I’m happy her album is coming out. She’s taking us into her circus and I’m enjoying it.”

“It’s going to be great to see her,” Bass added. “I’m so proud of her. I’m really happy. I don’t think she went anywhere. I think the album is amazing. I’m already falling in love with it.”

As she was presented with a circus-themed birthday cake, Barry Weiss, CEO and president of Jive Records, Brit’s label, told the singer, “We are so proud and so happy to be a part of your life. Looking at your two boys today, it’s an amazing experience.”

From two psychiatric evaluations, to losing custody of her sons, to a triumphant return to the top of the pop echelon, Britney Spears knows her 2008 has been one rollercoaster of a ride.

“This whole year has been a hell of a year for me,” Spears tells Glamour magazine in its January 2009 issue. “I have ‘come back’ so many times, people are just like, Is this another one? …It’s kind of like a joke to me now.”

Admitting that she “didn’t know exactly where I stood with everyone,” Spears says it was her big night at the Video Music Awards, where she picked up three trophies, that made her realize people do want her to give them more. “When I received the awards and [the audience] stood for me, it showed me how much love is out there,” she says.

As she prepares for the Tuesday release of Circus, which coincides with her 27th birthday, the singer hopes fans will hear its “really personal” tone.

“Recording this album has helped take my mind off certain things,” she says. “For me, my music is therapy …It’s me talking to them, instead of just singing a song about something.”

Spears, who reiterated she prefers being a homebody to partying nowadays, also has high — and stable — hopes for 2009 and the future as she closes the chapter on a whirlwind 2008.

“I would like to stop worrying so much, because I worry all the time. And to learn how to be happier, just in general,” she said. “In five years I would like to be married and have a father figure for my kids, someone who is a provider and can be really stable. It’s hard doing it on your own.”

Where does Britney stand with you? Will Circus complete her “comeback,” or is her comeback still in the making?

Britney Spears said she plans to make her first international tour since 2004 to support her highly anticipated new album, “Circus.”

In an interview broadcast on Monday by New York radio station Z100, Spears was asked if she planned to tour.

“Oh definitely, next year,” she said, adding the tour would probably take her “around the world.”

That would mark her first major concert tour since 2004.

Last year, Spears performed in a handful of club shows in Southern California under the name the M+M’s but did not go on the road to promote her last album, “Blackout,” which had a good chart debut in November 2007 but faded quickly.

After more than a year of making headlines for shaving her head, attacking paparazzi with an umbrella and two admissions to psychiatric hospital units, Spears, 26, is preparing for a comeback.

Her last live public performance was a much-ridiculed rendition of “Gimme More” at the MTV Video Music Awards a year ago.

The singer’s latest single, “Womanizer,” was released on Friday and is the first single off “Circus,” which will be released on December 2 — her 27th birthday. She told Z100 she spent six months working on the album