(Cover) - EN Showbiz - Adele was reportedly forced to turn down the opportunity to perform with pop superstar Beyonc Knowles at the weekend due to illness.

The American star was the first solo female performer to headline at the prestigious Glastonbury music festival and wanted to share the stage with Adele.

But the 23-year-old singer has been suffering from laryngitis for the past couple of weeks which saw her have to cancel several dates from her US tour.

Adele has been under strict instructions from her doctors to not use her voice which meant that the collaboration with the Single Ladies singer would have been impossible.

The big-voiced songstress is said to be very upset at having missed out on the great opportunity.

"Adele was absolutely gutted, Beyonc is one of her big heroes," an insider told British newspaper The Sun.

"It would have been the stuff of dreams to perform with her the gig of her life.

"But docs have told her she's got to rest her voice or risk damaging her prized asset. She hopes one day they can do something together."

Although there were rumblings from die-hard festival fans about an R&B singer headlining the Pyramid Stage, Beyonc won over the crowd with her energetic 17-song set last night.

She later described singing to the 170,000 strong crowd as the "highlight of her career." (C) Cover Media