During the final song of the 15-minute set in California someone in the audience threw a which just missed her head.

Her bodyguard immediately whisked Britney, 25, off stage.

Near miss: an object was hurled at Britney during her second concert

She's done it again: a healthy looking Britney back after three years away from the stage

Britney devised her own routines for the show

Before the incident, in Anaheim, the singer, who was in rehab earlier this year, made a drug gesture while singing her hit Toxic.

A source said: "There is a line 'I need a hit, baby give me it' and Britney put her finger to her nose pretending she was doing a line of coke. Then she gave a cheeky smile."

The night before, she was three hours late for her first comeback concert and performed for a mere 14 minutes and there were suspicions that she mimed to a backing track.

Her high-energy appearance alongside six backing dancers, however, delighted most of the 300 fans who crowded into a tiny California club.

It is less than three months since Spears was shaving her head, yo-yoing in and out of rehab and attacking a photographer with an umbrella.

For Spears, the performance marked an extraordinary comeback from the brink of meltdown.

The pop princess's return had been cloaked in secrecy with the concert advertised as "the M&Ms" - an apparent reference to her change from a Mrs to a Ms in the wake of her divorce from Kevin Federline.

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Buff and bronzed: Britney showed off her newly slender physique

The crowd cheers Britney on during her first show in three years

Britney first performance included just five songs

But as rumors spread on the Internet that Britney was the star of the show, tickets which had been on sale for were changing hands for as much as

There was mayhem on the streets near the House of Blues club in San Diego, where fans crowding the pavements were jostled by the star's six heavily-muscled minders.

A tearful Maria Edwards, 19, said: "I was shoved out of the way and fell to the ground in all the chaos. We just wanted to get pictures of Britney but her security guards were going crazy at everyone and being really heavy-handed."

Britney (center) on stage with her back-up dancers

Britney's entourage, and accompanying paparazzi, caused chaos on the streets

Fans hoped to catch a glimpse of the star on her tour bus

The show was due to start at 7.30pm, but it was 10.40 when it eventually began.

Wearing a brunette wig, white knee boots, a pink jeweled bikini top and white mini-skirt, a newly-slim Miss Spears danced her way through a set including Baby One More Time, Toxic and Breathe On Me.

One audience member, Morgan Segall, 20, said: "It looked like she lip-synched her way through the whole thing."

But Rich Abrahams, 22, said: "This is what Britney fans have been waiting for. It is the start of something bigger and better and is an historic moment in pop history."

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