Pop star was supposed to perform at the Billboard Awards this weekend
Las Vegas event is due to be held this weekend
Singer recently lost a legal bid to be released from her contract with the producer
Singer says she is 'happy as a damn clam'
Songwriter Diane Warren was honoured at the benefit in Los Angeles
The singer will hit the road in July
The attorney was sued for defamation by Dr. Luke
'True Colours' is streaming now
Pebe Selbert had accused the producer of 'intentional and negligent infliction of emotional distress'
The pair teamed up live at Coachella Festival earlier this month (April)