"Yes it's true ... it finally happened, I've lost my voice," Welch posted on her official Twitter feed. "I've sustained a vocal injury and been told I cannot sing for a week ... seriously I felt something snap, it was very frightening."

Welch, 25, canceled a performance for Thursday at Spain's Benicassim festival and one for Saturday at Portugal's Optimus Alive! festival.

The "Dog Days Are Over" singer, whose distinctive voice and style have been the band's hallmark during their rise to fame, said she was told to stop performing to avoid permanent damage. She gave no further details about her condition.

The singer later tweeted, "Thank you for your get well message's. I can't tell you how much I appreciate your love and support..xxxx"

Florence + The Machine are midway through their summer festival tour, which they kicked off with the Coachella Valley Music and Arts festival in April in Indio, California. They are expected to perform at various festivals across North America and the United Kingdom through September.

Last year, singers Adele and John Mayer canceled performances because of vocal injuries.

(Reporting By Piya Sinha-Roy; Editing by Bob Tourtellotte)

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