Pop star Britney Spears has canceled two of her Las Vegas shows after injuring her ankle in a fall during a performance. The “Toxic” and “Circus” singer took a tumble on Wednesday during one of her “Britney: Piece of Me” residency concerts at Las Vegas’s Planet Hollywood resort and casino. Caesars Entertainment, which owns Planet Hollywood and resorts and casinos, said in a statement, “Britney injured her ankle during her performance Wednesday evening and her doctor has advised her not to perform Friday and Saturday evening so that she may heal.”