Rihanna is apparently too sick to sing again.
Live Nation announced that Monday night's show in Houston will not go on "as a result of illness," but the concert promoter stated that people should hang on to their tickets so that they can be honored at a later date.
Rihanna previously missed two dates on her Diamonds World Tour in March due to laryngitis.
There's been no explanation from Ri-Ri yet, the only tweeted missive today being a happy birthday message to her brother Rajad.
She reportedly attended a pal's birthday party at Marquee in Las Vegas on Friday, along with opening act A$AP Rocky and Snoop Lion.
Rihanna's tour is supposed to touch down in Dallas tomorrow.