Metallica look set for a summer show at Knebworth, with rumours suggesting it could be part of a three-day rock festival to rival Download.
The metal giants will reportedly play an exclusive headline set at the new festival, which is being penned for the Hertfordshire stately home in July 2009.
It is believed that Muse and Red Hot Chili Peppers have also been approached for the event, which would be the first time the historic venue has been used for a full-scale festival.
If it goes ahead it could rival the more established Download festival, which takes place at Donington Park, Leicestershire, from 12-14 June.
Knebworth's managing director, Martha Lytton Cobbold, refused to rule out the possibility of a new music festival going ahead.
She told the Welwyn and Hatfield Times: "We would entertain holding a festival here."
And when asked if Metallica would be made welcome, she replied "sure", adding: "They are very popular throughout Europe."
Virtual Festivals believes the event is being organised by Kilimanjaro, a promotions company founded by former Download director, Stuart Galbraith, before he left Live Nation. The company refused to comment on the rumours when we contacted them.
Knebworth has been used as a live music venue for the last 40 years and has hosted the likes of Oasis, The Rolling Stones, Led Zeppelin, Queen and Pink Floyd.
Robbie Williams was the last big name act to play Knebworth, selling out three nights in 2003.