After already cancelling one of her 'Diamonds' tour dates, Bajan beauty Rihanna has now postponed yet another concert on her North American tour due to laryngitis.

She kicked off the extensive run of dates with a show in Buffalo, New York over the weekend but had to cancel her Boston date on Sunday night (March 10) after being diagnosed with the condition.

Rihanna was due to perform at the 1st Mariner Arena in Baltimore, Maryland tonight, but a message on the venue's official website confirms that the gig has been called off. Radio station Z104.3 also posted a short news article giving fans an update on the situation, which explains:

"Unfortunately, Rihanna is still recovering from the flu and laryngitis and plans to perform again in Philadelphia, PA on Thursday, March 14. Fans are instructed to retain their tickets pending rescheduling show date information."

Writing on her official Twitter page recently, the 'Umbrella' sensation apologised to her fans and confessed that she is "embarrassed" at having to cancel shows because she hates letting people down: "I hate disappointing people that never ever let me down!! I'm so embarrassed about this! Thank you for your prayers and well wishes! #DWT."

Watch Rihanna's 'Leaving For Buffalo' pre-tour footage below: