Going out with a bang! Demi Lovato rocks into action as she ends tour at Brazil's Z Festival

She was spotted looking absolutely shattered as she arrived in Rio de Janeiro on Friday, make-up free and clutching to a pillow. But after some much-deserved rest Demi Lovato was back on top form the following day as she performed in concert on Saturday. The X Factor USA judge appeared at the Z Festival and looked ready to rock in her trendy attire. Ready to rock: Young singer Demi Lovato performed at the Z Festival in Rio de Janeiro, Brazil Ready to rock: Demi Lovato performed at the Z Festival in Rio de Janeiro, Brazil The 20-year-old donned a sexy pair of leather trousers and a spike studded jacket to match. She stayed cool under the stage lighting with black top featuring a skull design. Dressed up: The X Factor USA judge was leather-clad at the concert on Saturday Dressed up: The X Factor USA judge was leather-clad at the concert on Saturday Whipping her hair: The 20-year-old put on an energetic performance Whipping her hair: The 20-year-old put on an energetic performance Hard-working: Demi's gig was a final stop on her tour Hard-working: Demi's gig was a final stop on her tour The funky ripped-style vest enabled a lacy bralet to be seen underneath and showed off a necklace formed from several gold chains. The blonde appeared to be highly enthusiastic about her performance as she whipped her hair back and forth on the stage. Singing in front of a live band, the TV talent show panellist's energetic routine pushed her limits as she could be seen getting out of breath after dancing closely with her guitarists. Lovato was outside of the United States while The X Factor's second series in America is underway - before the live show stages. Getting close: The star moved in on one of her band members Getting close: The star moved in on one of her band members Heated show: The former Disney star oozed sex appeal on stage Heated show: The former Disney star oozed sex appeal on stage New panellist: She is gearing up for the live stages of The X Factor New panellist: Demi is gearing up for the live stages of The X Factor The star and fellow new judge Britney Spears, as well as music executive L.A. Reid and boss Simon Cowell have already recorded the Judges' Houses section of the series, in which they decide who will perform live in front of millions of home viewers. Demi took advantage of her time off, heading to Brazil to play the final date of her Demi Lovato Summer Tour 2012. The tour began in June, starting in Del Mar, California, before moving across the U.S. and Canada, and then culminating in South America. Shattered: Lovato looked tired as she arrived at Rio de Janeiro International Airport Shattered: Demi looked tired as she arrived at Rio de Janeiro International Airport on Friday