There's no denying Beyonce's work ethic. After all, this is the same woman who performed a series of comeback shows just four months after giving birth to Blue Ivy last year. But even the best at their craft have a bad day now and then. Yesterday, the singer was forced to postpone a show in Antwerp due to "dehydration and exhaustion." As a result, she's written a heartfelt apology to fans for the missed show.

"To my dearest fans in Antwerp," Beyonce wrote in the handwritten letter featured on her website. "I've never postponed a show in my life. It was very hard for me. I promise I will make it up very soon. I'm sorry if I disappointed you."

Bey goes on to thank her supporters for their support during this time. "Thank you for your concern," she continues. "I'm feeling much better now. And I'm ready to give you a great show. "

This evening she'll take the stage for her second scheduled show in Antwerp, a stop on the Mrs. Carter World tour. The tour kicked off in Serbia on April 15 and will come to a close on August 5 at Brooklyn's Barclays Center.

Thus far, the ''Bow Down" songstress has taken the stage for 20 dates on the trek. There are 11 European shows left before she returns to the U.S., performing in Los Angeles on June 28.

News of Beyonce's canceled Antwerp show further fueled rumors that she's expecting her second child with Jay-Z. At a London show on May 4, when she brought Blue Ivy out onstage, photos captured of the moment showed Beyonce's stomach protruding a bit more than usual. According to MTV, a representative for the former Destiny's Child frontwoman did not return requests to comment on the pregnancy rumors.