The singer ditched the designer frocks and immaculate hair and make-up for a pair of denim shorts, floral shirt and obligatory wellies.
But just in case anyone was about to mistake her for a regular festival goer, she accessorised her look with a mini designer handbag and pair of oversized shades.
She completed her festival ensemble with a some flowers in her hair. Very Woodstock.
The 32-year-old classical singer is amongst the first celebs to arrive at Worthy Farm in Somerset.
And Wayne and Coleen Rooney are also expected to rock up today after tweeting a snap of them with a group of friends just before they boarded a chopper to fly them to the site.
The Rooneys and chums prepare to fly to Glasto
We have a feeling they won't be slumming it in a tent either.