After a dismal performance in Belgrade, Serbia on Saturday that had the British singer stumbling around the stage, barely able to stand or perform, Amy Winehouse has decided to cancel the rest of her summer tour.

"Despite feeling sure that she wanted to fulfill these commitments, she has agreed with management that she cannot perform to the best of her ability and will return home," her reps said. "She would like to apologize to fans expecting to see her at the shows but feels that this is the right thing to do."

Winehouse has been battling substance abuse, checking and out of rehab as recently as this past May. Her latest European tour was originally slated to run until August 15.

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