The 68-year-old singer, who is currently on her Blue Smoke World Tour, will be performing at the festival tomorrow, reported BBC news.
"We're really, really excited because it's been something we've been wanting to happen for a long time. And she finally said yes," Glastonbury organiser Emily Eavis said recently.
Parton also announced the news to her fans via Twitter.
"I'm incredibly excited to finally announce that the Blue Smoke World Tour is coming to Glastonbury festival on June 29th! Stay tuned for more information, Parton wrote.