The singer's mind went blank midway through a performance of "Don't Know Why" at Whoopi Goldberg's "Rainforest Action Network" gala at Manhattan bar the Plumm on Saturday.
Jones eventually recovered her composure - but not without skipping some of the lines.
An audience member tells PageSix.com, "She looked confused and just sat there for a minute. Then she said, 'Sorry about that,' and started up again - but she left two lines out."