Britney mimes again at birthday show

Britney Spears tried to put her widely-criticised appearance on X Factor behind her today as she celebrated her 27th birthday with a special show on US television.

The troubled pop star continued the launch of her sixth studio album, Circus - her first since her attempted comeback with Blackout last year - during the tribute on ABC's Good Morning America.

But she mimed the lyrics and even the show's co-host Diane Sawyer referred to how she wished the troubled pop star would "sit and talk to us".

Instead, Spears gave almost one-word answers to a couple of questions after her performance and even appeared to struggle to answer where her concert tour kicks off, eventually saying "America".

It was left to the breakfast programme hosts to clarify that it begins in New Orleans on March 3.

Wearing a ringmaster's costume, Spears was accompanied by clowns, jugglers and performers dressed as circus animals for the title song of her new CD.

She then jumped though a fiery hoop for her performance of her current single Womanizer inside the Big Apple Circus tent at the Lincoln Centre in New York.

US showbiz website TMZ said: "What Britney lacked in dance moves on 'Good Morning America', she definitely made up for in the ab department.

"Spears brought her now infamous 'Womanizer' strutting/arm-flailing routine to a new song, 'Circus' but her stomach made for quite the distraction."

Spears was watched by her two young sons, Sean Preston, three, and Jayden James, two, and her mother Lynne, who were in the audience.

A series of high-profile celebrities also delivered recorded birthday greetings for the star.

These included Reese Witherspoon, John Travolta, Teri Hatcher and Hugh Jackman - who sang "Happy Birthday" and blew her a kiss despite admitting he had never met her.

"You look great," Witherspoon said to Spears.

"And I hope you have a great day."

Spears was celebrating her birthday as she revealed in a documentary, screened both in the UK and the US, that she was finding it difficult to meet a new man because she no longer trusted anyone.

"I let people in because I was lonely and I really paid the consequences for that big time," she told the documentary Britney: For the Record, which screened on Sky One in the UK.

"I am very protective of myself. Sometimes it can get kind of lonely."

The star, who has become known more for her turbulent private life than her music after her divorce from Kevin Federline, was also the UK's most searched-for subject on the internet this year, Yahoo! said.

Interest in the pop star propelled her to first place in the website's list of the top 10 searches for 2008 - beating a host of showbiz-focused searches and even the US elections.

Her US TV appearance also came after she was widely criticised in the UK at the weekend for struggling to synch her lips in time to the music on X Factor.

It was also reported she travelled with a 45-strong entourage of stylists and security for the show, banned contestants and judges from approaching her, and, unlike previous guests including Mariah Carey, Take That and Girls Aloud, did not coach the contestants.