Black Sabbath's Back to the Beginning farewell gig is rocking out Birmingham today
"Without Sabbath there would be no Metallica" - James Hetfield
Every band are doing their own tribute to Black Sabbath by covering one of their songs
Steven Tyler, of Aerosmith and the Rolling Stones' Ronnie Wood have been among the guests at Villa Park
The gig will be the band's final performance, Ozzy Osbourne said
Fans have descended on Birmingham for the concert and those without tickets said they were here for the "vibes"
All you need to know about the farewell gig
Best view in Villa Park?
Among the tickets fans could buy were ones on the side of the stage to watch the gig.
The cost to do so? More than £2,000 a ticket.
Of course all the proceeds from the gig go to three charities - Cure Parkinson’s, Birmingham Children’s Hospital and Acorns Children’s Hospice.
PJ Ellis
BBC Radio WM
Ingo and Derya from Germany are in Birmingham for the first time and they are huge Black Sabbath fans.
Like many in the city, they haven’t got tickets, but are still in the city centre enjoying themselves.
They’ve come to visit Black Sabbath hotspots, like Ozzy’s house, reports Preeti Kular.
Ian Youngs
Culture reporter
"Birming-ham!" shouts Metallica's James Hetfield to the crowd.
The US rock gods are ripping up the stage with a suitably heavy set.
"Look at all this love for heavy metal. We’re so grateful to be invited," Hetfield says.
He pays tribute to the men in whose honour this show is being held. "Without Sabbath there would be no Metallica. Thank you for giving us a purpose in life."
Metallica have walked on stage and this place has erupted.
Ben Sidwell
BBC Midlands Today
Every band playing here today are doing their own tribute to Black Sabbath by covering one of their songs.
Each time you hear one, you can just hear those riffs from Tony Iommi that created the heavy metal sound.
Now a local lad takes the stage....this Mr Slash, from Stoke-on-Trent, is quite a good guitar player isn’t he?!
For Slash - real name Saul Hudson - this night - along with their concert a couple of weeks ago - marks a return to the Midlands, of sorts.
In what is surely one of Stoke-on-Trent's best facts, the musician was raised in Blurton until the age of six.
Try that one out at your local tomorrow.
BBC Radio WM presenter Ed James said: "The atmosphere here is literally incredible. I really can't hear myself think. I can't hear my own voice.
"It's a massive stage, it's as high as Villa Park itself. There are two massive stacks of speakers either side of the stage and two huge screens.
"It's the largest stage I've ever seen at Villa Park and there are 40,000 people going absolutely crazy.
"There are people on shoulders, there are massive beach-balls. It's a wall of noise and the energy and the atmosphere here it's like nothing I've ever experienced."
Ben Sidwell
BBC Midlands Today, Villa Park
Did someone book the wrong tickets?
Fans are wearing T-shirts from pretty much every rock and metal band you could imagine here.
Well, not just rock and metal...
I have to admit I wasn’t expecting to see this one here today though - brave man, though I'm sure he'll Shake It Off.
Leona Smart
BBC Radio WM
Guns N' Roses came on and the whole crowd slowed down, really matching the evening sun going down - just a moment of slight calm (and I say calm loosely).
BBC Radio WM presenter Ed James has just pointed out they were only here a fortnight ago - "they cannot keep away, they love the place".
Ed also said the guys have been "speaking to the crowd and you can just sense the atmosphere starting to build - everyone is here".
Let’s just say we’re glad the intro to Welcome To The Jungle wasn’t live.
Axl Rose offered up a lot of swears - the crowd then went wild for the opening guitar chords.
Leona Smart
BBC Radio WM
It’s incredibly incredibly loud!
The radio team have got all the kit turned up to the max and we’re still shouting to hear each other.
The view from here, a box at Villa Park, shows us multiple little mosh pits.
The crowd is moving as one at some points. Lots of tops off as the evening sun is shining down on a big part of the crowd.
Ben Sidwell
BBC Midlands Today
Next up...Guns N’ Roses!!
Ben Sidwell
BBC Midlands Today
Slayer are the latest band on stage and the mosh pit is in full flow.
So good they’re even showing it on the big screens!
This shows the scale of it...good luck spotting yourself!
Sarah Julian
BBC Radio WM, Aston
Cool outfits outside the stadium from Graham and Zoe.
They’re from Bury St Edmunds and won a competition to be here!
Wait, hold on! There’s a heavy metal guitarist on stage with no visible tattoos.
That said, Pantera’s Zakk Wylde’s got one heck of a beard though!
Ed James (centre) is all smiles just ahead of this evening's programme on BBC Radio WM, live from Villa Park - Back To The Beginning.
There's due to be commentary, interviews and atmosphere from the big night.
You can listen to his programme until 22:00 BST on 95.6FM, DAB and BBC Sounds.
Producer Leona Smart and engineer Andy Walters are enjoying it too...
Wouldn’t be an Ozzy gig without a bat somewhere around.
Think it’s a safe distance from the stage. Very sensible when the Prince of Darkness is around!
Ian Youngs
Entertainment and Arts reporter
Pantera frontman Phil Anselmo told the crowd the artists on the bill "would all be different people" without Black Sabbath.
"That's the truth. I wouldn't be up here with this microphone in my hand without Black Sabbath. The greatest of all time," he added.
He then led the crowd in a chant of the band's name before adding: "Love you, love Black Sabbath, man."
Shaggy and Mick from Cannock have been speaking to PJ from BBC Radio WM.
They could not get tickets, but said they still came to Birmingham for the buzz, to carry on the party vibes.
Ben Sidwell
BBC Midlands Today, Villa Park
The crowd have just been treated to a video of Jack Black and some incredibly talented youngsters - no doubt from the School of Rock - who belted out the Ozzy classic "Mr Crowley".
Of course, Black knows all about the rock genre himself - he's lead singer and guitarist for the duo Tenacious D.