He had been after them for years but AC/DC, one of the world's biggest rock bands, don't do festivals. Or didn't. "They do their own thing, their own stadium tours," says Andy Copping, Download's band booker. "They're the biggest rock band in the world. Back In Black is the biggest selling album of all time after Michael Jackson's Thriller. They played Wembley Arena last year and sold it out in a day. That's 70,000 people. So they don't need to do festivals.
"That said, I still wanted them for Download 2010 and had already tried twice.
"Then late last year, I was at a function and I left early to go back to the office. I say early but it was around midnight and I was just finishing off a few e-mails. I already had Them Crooked Vultures down to headline one of the days. And I thought, Them Crooked Vultures is cool..."
(The supergroup features Led Zeppelin's John Paul Jones, Foo Fighters frontman Dave Grohl and Josh Homme, of Queens of the Stone Age)
"... but I didn't think the announcement would have that 'Wow!' factor. So I decided to go after AC/DC again.
"But this time I sent a pitch to them as if I was in the band. What would make me want to play Download, other than a big chunk of money?"
So I sent a short note that said something like, 'I know you've already turned me down but I'd really like you to take into account...' and then I had these bullets points – 'it's the 30th anniversary of Donington; it's 30 years since Back In Black; we have Radio 1 on board; you can have a say in the bands that you want to play and we can accommodate your own stage production'.
"And I added, 'Maurice Jones, who I know you were close to and who launched Monsters Of Rock in 1980' with a guy called Paul Loasby, 'died last year. We want to pay tribute to him at Download and it would be a fitting tribute if you would play.'
" I sent this off to the band's agent in the US. By now it's half past midnight. I ring to check he's got it and his PA says he's not in the office, he's out with one of his bands.
"But then my Blackberry flashes and it's this guy. By pure chance he's sat with AC/DC's manager in Buenos Aires. He's shown him my e-mail, the manager shows it to (AC/DC guitarist) Malcolm Young and he's gone off to talk to the rest of the band.
"I couldn't believe it.
"There were a few more e-mails between us into the night and he said 'I think they're going to do it.'
"Bear in mind, negotiating deals with headline bands normally takes months. This was done in minutes.
"Every other festival organiser has either rang or e-mailed me going 'how did you do that?' And I've said 'I don't know. Lady Luck was on my side.'"
It is the first time AC/DC will have appeared at Download but the veteran rockers played Monsters of Rock in 1981, 1984 and 1991.
"I saw them each time," says Andy, who was at the first Monsters Of Rock in 1980.
"In 1981 it rained virtually all day, but nobody cared because we were all there to see these bands. I saw them again in 1984 with Van Halen, Ozzy, Motley Crue and Scorpions on the bill. And then in 1991 with Metallica."
Joining AC/DC at Download this summer are Them Crooked Vultures (no longer headlining), Motorhead, Deftones, Stone Temple Pilots, Megadeth, Bullet For My Valentine and Wolfmother.
None of Them Crooked Vultures has ever played at Donington. Neither have grunge-rockers Stone Temple Pilots although frontman Scott Weiland has twice with Velvet Revolver.
It'll be thrash metallers Megadeth's fourth time, after 1988, 2005 and 2007, likewise Motorhead (1986, 2005 and 2008).
Andy, who worked at Rock City on and off from the late80s until seven years ago when he joined Download promoters Live Nation, has yet to finalise the other two headliners.
"I'm stitching those up at the moment and expect to announce them in a couple of weeks."
Does it matter? Can't AC/DC sell-out the 110,000 tickets on their own?
"We'll see when the tickets go on sale. It would be an incredible feat. But I've only just started. I've only booked 10% of the line-up so far. We're not taking our foot off the gas in terms of getting great bands for the other two days. We're still doing three days, we're still doing four or even five stages."
The increased capacity, if a sell-out, will be a record for Donington. In 1988 there were 107,000 people.
Last year's 85,000 daily attendance was Download's first sell-out.
"It was amazing to see kids in Slipknot T-shirts watching Def Leppard and guys in Whitesnake shirts watching Trivium.
"Corey Taylor, the singer from Slipknot, wanted to meet the guys out of Faith No More and he was tongue-tied, like an eight-year-old kid. Slipknot were headlining the following night but he was nearly crying meeting his heroes."
Monsters of Rock and the first few Downloads were held within the Donington racetrack. In 2008 they moved off to make way for the planned redevelopment of the track for Formula 1.
"It's a shame that whole thing has fallen apart," said Andy. "But Kevin Wheatcroft, the landowner, said he wanted the festival to stay at Donington. Whatever happens with the race circuit, we're not affected.
"Where we are now allows us to expand both the capacity and the campsite.
"We're right on the flight path of East Midlands Airport. There's nothing like standing in that field and seeing those planes go over."
Download 2010 , Donington Park, Leicestershire, June 11 to 13, Tickets: Weekend – £145; standard or family camping (three days) – £25; (five days) – £35; camper van supplement – £40; campsite lockers – £11; parking £15/£20.