Damon Albarn and the Orchestra Of Syrian Musicians will be the first act on the Pyramid Stage at 11am, ushering in three days of performances from hundreds of acts.
Other musicians scheduled to perform on Friday include indie act Foals, grime artists Skepta and Stormzy, rising star Jack Garratt and electronic music duo Disclosure.
Fans will wake up to find out the result of the EU referendum, with news coming through early in the morning about whether the UK is In or Out.
The first day of music could also be marred by worsening mud and heavy showers, as the Met Office has forecast rain during the afternoon.
