Ke$ha performs with Joan Jett in Las Vegas

Pop star Ke$Ha thrilled the crowd at a music festival in Las Vegas on Saturday night (21Sep13) by performing with rock legend Joan Jett.

The TiK ToK hitmaker was on the bill for the iHeartRadio Fest in Sin City over the weekend (21-22Sep13), along with stars including Miley Cyrus, Katy Perry and Justin Timberlake, but she had an extra special surprise in store for the audience.

After performing her hit Die Young, Ke$ha introduced music veteran Jett to the stage for a rendition of the rocker's classic 1980 hit Bad Reputation.

Ke$ha previously hinted about a "surprise" she had planned for the show in posts on her Twitter.com page in the run up to the gig.