Pop princess Britney Spears showed up in Anaheim Wednesday night for her second "impromptu" performance in as many nights.

Fans received the second set at the House of Blues in Anaheim even less welcoming than the first, according to witness accounts from PerezHilton.com.

According to the report, Spears was getting through her "Toxic" number when something the size of a marshmellow came flying out of the crowd and nearly missed Britney.

At that point, her security quickly took her off stage, with Britney simply saying "Thank you so much" to those attending.

Other witness accounts say the fallen pop diva didn't even perform full versions of her hits (lipsynching everything again) but rather danced to shortened mixes of said tunes.

Britney Spears performed for the first time in more than three years on Tuesday, making a brief, unadvertised appearance at a San Diego nightclub, local media reported.

The gig, which reportedly lasted between 15 and 20 minutes, was not exactly a surprise. Rumors had run rampant in the past few days that three scheduled southern California shows featuring an unknown band called The M&M's were a cover for the troubled pop princess.

A television news report said $35 tickets for Tuesday's show at the 1,000-capacity House of Blues changed hands for as much as $500. The M&M's are also scheduled to play at House of Blues outlets on Wednesday near Disneyland and on Thursday on the Sunset Strip in Los Angeles.

Spears' arrival at the San Diego venue was greeted by a horde of aggressive paparazzi and excited fans.

Wearing a brunette wig, a short top and skirt and tall boots, she performed five of her songs, and barely addressed the crowd, according to fans.

"I think she worked the stage, her body looked great. So it was good to see her finally come back and prove us all wrong," a female fan told Los Angeles TV station KNBC.

Spears, 25, whose professional achievements have been overshadowed by her personal crises, has not released an album since 2003. In that time, pop rivals like Christina Aguilera and Justin Timberlake have seen their careers soar.

Shortly after her 2004 marriage to her second husband, aspiring rapper Kevin Federline, Spears announced she would take some time off "to enjoy life" and "just chill."

Spears gave birth to two children, hit the Hollywood party scene and began behaving erratically. Far from her early image as a coquettish virgin, Spears generated headlines with her antics and was photographed in December wearing no underwear under her skirt. She appeared to hit bottom in February when she tearfully shaved her head, and then entered rehab for undisclosed problems.

There are signs that Spears is now refocusing on her career. After leaving rehab in March, she promptly finalized a divorce agreement with Federline, and fired her manager, Larry Rudolph.

She is reportedly recording her fifth album, which she started working on last year with red-hot hitmakers like R&B singer Ne-Yo and Swedish producer Max Martin.