Britney Spears clocks up eight costume changes in less than four minutes for TV return

The troubled pop star polished up her act for her guest spot on sitcom How I Met Your Mother, which aired in the US last night.

The show's stylists banished her personal wardrobe of scuffed knee-high boots, ripped fishnet stockings, cut-off denim hotpants and see-though tops, in favour of a more demure, feminine look.

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And now six items worn by the star during the show are going under the hammer for charity on auction site seenon.com, with her crème Nanette Lepore cardigan with blue beaded flowers leading the bidding at US$3,001.00 with still five days to go.

More than 10 million viewers tuned in to watch the star, drawing the show's highest-ever ratings.

She played a love-struck receptionist in a tattoo-removal clinic who falls for the main character Ted.

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The role marked a return to the small screen for Britney, who last made an appearance with a guest role in the hit US sitcom Will & Grace in 2006.

It was billed as the first step of a possible road to recovery for the 26-year-old and US TV critics agreed.

In the New York Post, Linda Stasi wrote: "You'd never know that pop tart Britney Spears had ever had a bad day in her life.

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"Now clean and sober and under her dad's thumb once again, Britney looked as adorable last night as she did waaay back when.

"On the show, which she filmed in the last few weeks, Brit looked slim, (OK she was behind a desk), trim and gorgeous.

"And, more importantly, her acting was nothing short of adorably believable. Good for her."

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Referring to her role in the show, Ms Stasi said: "She's not that innocent - but she still looks it. Welcome back."

David Hinckley, writing in the New York Daily News, added Britney showed "she can act".

"For those who hang on every one of Britney's career moves, this bold casting decision worked out," he wrote.

"The startling part about all this, of course, was seeing Spears on a television screen when she wasn't forgetting the words to one of her own songs or being chased by paparazzi.

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"But television has been the antidote to career suicide before, so perhaps Spears has been watching the 'Rob Lowe West Wing 10 Easy Episodes Back to Respectability Self-Help Video'."

Spears spent two days filming the scenes in which her character Abby falls for Ted in the show.

The move was a light-hearted departure from the months of erratic behaviour, child custody disputes and police stand-offs which have blighted the young star's life in recent months.

Producers said there were "no diva moments" and Josh Radnor, who plays Ted, told USA Today the cast tried to provide "a nice safe place" for Spears.

"It's a cute, funny role, and she ended up being great in it," he said.

"She's actually very vulnerable and sweet."

He went on: "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."

Previously the singer starred in the teen road movie Crossroads in 2002, which was described as "mindless drivel" by USA Today.