Katy Perry had to be rescued by security guards on Tuesday night (05Aug14) after she made an onstage promise to meet concert-goers following her show in Philadelphia.

The Teenage Dream hitmaker announced at the end of her concert at the Wells Fargo Centre that she would greet devotees at the top of the Philadelphia Museum of Art steps, which were made famous in boxing movie Rocky.

Hundreds of fans showed up to catch a glimpse of the star, who kept her word and made an appearance at the top of the steps in a printed 'onesie'. However, Perry was swamped by the crowd and security guards pulled her away and bundled her into a car amid fears for her safety.

The 29-year-old singer later assured fans that despite having to leave almost straight away, she had still kept her promise by showing up, writing in a post on Twitter.com, "I keep my promises Philly!"