Disappointing her hopeful Texas fans, Rihanna cancelled her show in Houston on Monday (April 15).

Live Nation announced that the show will not go on "as a result of illness," but told fans to keep their tickets for a later date.

Though an avid Tweeter, her Twitter account was silent on the matter, with Monday's comments being only birthday wishes to her brother and a message of support for the Boston Marathon victims.

Back in March, the 24-year-old singer missed two dates on her Diamonds World Tour because of laryngitis.