Katy Perry reported for duty at Madison Square Garden last night in a very skimpy toy soldier costume.The 26-year-old singer teamed her festive - and rather flirty - costume with thigh-high white boots and fishnet stockings for Z100’s Jingle Ball in New York.

She was joined by no less than three Santas as she cavorted around while performing a medley of her hit songs.

She sang her latest number one hit, Firework, along with Hot & Cold, I Kissed A Girl, Teenage Dream and crowd favourite, California Gurls. Katy was joined by a host of other stars for the event, including Disney star Selena Gomez.

The 18-year-old star, who was dressed in a low-cut black gown, performed her tracks Round and Round, A Year Without Rain, and Naturally. She earlier walked the red carpet alone, careful to keep her distance from fellow performer Justin Bieber.

The teen stars sparked rumours of a romance after they were spotted at an International House of Pancakes in Philadelphia on Wednesday.

Onlookers said they were holding hands at the restaurant and a camera caught them leaving arm in arm. Selena has previously described Justin as 'one of my best friends.'

Katy Perry At Top Of Hot 100

Katy Perry has topped the Billboard Hot 100 chart with her latest single "Firework." It bumps last week's number 1 song, Pink's "Raise Your Glass," to number 2.

The song also makes Perry the first female singer in 11 years to have three consecutive singles from an album reach number 1 on the Billboard charts.

Perry's single, the third from her hit album Teenage Dream, has spent seven weeks on the Billboard Hot 100 chart. It also charted at number 1 on the Digital Songs chart, number 7 on the Pop Songs chart, and number 8 on the Radio Songs chart.

Perry recently received nominations for the 53rd Grammy Awards including Album of the Year for Teenage Dream and Best Pop Collaboration with Vocals for "California Gurls" featuring Snoop Dogg. Teenage Dream and "California Gurls" are both also nominated for Best Female Pop Vocal Performance.

Teenage Dream debuted at number 1 on Billboard 200 chart selling 192,000 copies in its first week.