Britney Spears has had mixed fortunes over the last 24 hours.

A court defeat and a comedy cameo were all in a day’s headline-generating work for the troubled 26-year-old star.

There was little for Britney to laugh about when an appeal court threw out her challenge to an order giving her father much control over her assets and personal life.

James Spears was made a co-conservator of his daughter’s estate in February, after she was twice hospitalized in a psychiatric facility.

Yesterday, Spears’s bid to challenge that order collapsed when a judge in California ruled that it was not within his powers to grant an appeal.

But Easter Monday was, it seems, a day for comebacks as well as setbacks.

Spears’s guest appearance on the comedy show How I Met Your Mother was screened in the US last night, sparking much speculation that her career may be back on an upward trajectory.

Playing the part of Abby, a ditsy doctor's receptionist with a crush on main character, Ted, she returned to the small screen for the first time since her guest role in the hit US sitcom Will and Grace in 2006.

And while not all the reviews were exactly sparkling, Miss Spears received a general thumbs-up for her performance.

“There’s not a lot to say about Britney Spears’s cameo on “How I Met Your Mother” last night”, said Roger Friedman of Fox News.

“She had nice comic timing for her few lines, seemed spunky, alert and with it. Considering the last 18 months of her chaotic life, all of that equals a success.”

Matthew Gilbert of the Boston Globe wrote: “No, Britney Spears did not become an overnight comedy sensation last night during her guest spot on How I Met Your Mother. Viewers were nor left crying out, 'Gimme More'. But then Our Lady of Perpetual Melodrama won't be an object of ridicule today, either, as she was after her schleppy MTV Awards performance last fall. She was O – wait for it – K.”

And despite Spears’s questionable acting credentials – she won a worst actress Razzie for her part in the 2002 movie Crossroads – her HIMYM co-star Josh Radnor, who plays Ted, was complimentary: “It’s a cute, funny role, and she ended up being great in it,” he said.

“She’s actually very vulnerable and sweet. We both screwed up our lines (during taping) and made fun of ourselves.

“She definitely has comedic instincts. She made funny line readings (during script read-throughs). That’s the sign of a good comedic actor.”

The sitcom's executive producer, Carter Bays, told the American newspaper, USA Today: “There were no diva moments. She's a professional. Her people... her parents were there."

And it seems like the admiration was mutual. People, the American showbiz magazine, quoted Britney as saying: "Working on the show was terrific. Everyone including the cast, the crew, and the producers have been wonderful."

While her television future is unclear, meanwhile, there is no doubt that Miss Spears still has phenomenal power to attract attention.

Within minutes of the episode appearing on American television, an auction began for the clothes that the singer was wearing during her performance.

The money raised will go to the Natural Resources Defence Council, an environmental organisation.

Millions of people have already viewed clips of her cameo on YouTube.

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