PHOENIX (Reuters) - Chart-topping rapper DMX pleaded not guilty to a pair of felony theft charges in a Phoenix court on Thursday, and then treated reporters to an impromptu rap about bouncing back from adversity.

DMX, whose real name is Earl Simmons, was charged with one count of theft and one count of taking someone else's identity.

The charges stemmed from a visit Simmons made to the Mayo Clinic in Scottsdale, Arizona, in April during which he gave his name as "Troy Jones," allegedly to avoid paying for treatment.

After denying the charges, he serenaded reporters waiting outside the Maricopa County Superior Court.

"If and when you ever fall down, get back up," Simmons began, according to a censored recording on a local radio station's Web site.

"Drop something, stop fretting, pick that ... back up, stand for something or fall for everything, wait for the right pitch or miss with every swing," Simmons sang.

The 37-year-old rapper is next due to appear in court on Aug. 12.

Simmons, who has a home outside Phoenix, has been involved in a string of legal tangles. In May, he was arrested on suspicion of drug possession and animal cruelty after searches of his home allegedly turned up weapons, drugs, dog carcasses and abused pit bulls.

In 2006, he served more than two months at New York's Rikers Island jail in connection with a 2004 incident when he smashed his sport utility vehicle into a gate at John F. Kennedy Airport after identifying himself as a federal agent.

His first five albums opened at No. 1 on the U.S. pop album charts, but his most recent release, 2006's "Year of the Dog ... Again," ended that run by debuting at No. 2. Simmons has also acted in several action movies, including "Cradle 2 The Grave" and "Exit Wounds."