Fans delirious as Stevie Nicks joins Tom Petty on stage

It was Side A all the way when Tom Petty played the BST festival in Hyde Park on Sunday.

"We're going to look at the show like it's a giant one-sided vinyl," said the star, "and we're going to drop the needle all up and down the record."

The set included nearly two dozen classics, such as Free Fallin', I Won't Back Down and Learning To Fly.

Stevie Nicks joined him halfway through the set for a special version of their 1981 hit Stop Draggin' My Heart Around.

"You know that Tom Petty is my favourite rock star!" said the singer.

Fans were delighted by the duet; which trended on Twitter on Sunday night.

"Pure joy. Thank you," wrote one fan, posting a photo from the audience.

Nicks had earlier played a support slot, running through her Fleetwood Mac songbook with renditions of Dreams and Gold Dust Woman, alongside solo hits Edge of Seventeen and Landslide.

After playing Rhiannon, the 69-year-old noted she'd played the song at every concert since it was released in 1975.

"It's never not been done," she deadpanned. "Rhiannon: You just can't get rid of her."

Nicks also delved into her pre-fame catalogue with the Buckingham-Nicks song Crying In The Night which, she noted, was written in 1970, when she was a struggling musician working as a waitress in LA.

"Dreams do come true," she told the audience. "Because 44 years later you can sing a song you thought nobody would ever hear in Hyde Park in London, England."

Tom Petty's set was equally nostalgic, opening with footage of his band, The Heartbreakers, playing on the BBC's Old Grey Whistle Test.

The concert marked the 40th anniversary of the group which has, incredibly, retained almost all of its core members over the years - embellished on this tour by the gossamer harmonies of British singers The Webb Sisters.

On stage, the set-up was simple: just a bunch of amps, a few illuminated globes and an ever-changing parade of guitars - but that's because Petty never needs to distract the audience from the music.

His catalogue is so strong he can dispense with encore-worthy material like You Don't Know How It Feels and Free Fallin' in the first 30 minutes; prompting an enthusiastic singalong from a British audience who rarely get to see the band play (Petty last visited the UK in 2012, and before that in 1999).

Holly Willoughby, Jennifer Saunders, Adrian Edmondson, Sharon Horgan, Niall Horan, Laura Whitmore George Ezra, Alan Carr and Olivia and Dhani Harrison were among the famous fans who turned up to witness the open-air show, along with 65,000 other fans.

And their response was so overwhelming that this most well-seasoned of bands was occasionally taken aback.

As they wrapped up Mary Jane's Last Dance, the audience begin to holler the song's guitar riff - taking their cue from The White Stripes' Fell In Love With A Girl. which turned the hook into an "ah-ah-ah" chant in 2001.

"Well, thank you for that," drawls Petty, cueing the band to join in. "This is such a thrill for us."

He's not the most charismatic frontman, nor the strongest vocalist, but when The Heartbreakers are working in sync, none of that matters.

Guitarist Mike Campbell, resembling a better-preserved Jack Sparrow, delivers stinging solos on Runnin' Down A Dream and American Girl; while Brighton-born drummer Steven Ferrone locks the band in tempo with an astonishing dexterity.

Petty guides them here and there with an arm gesture or a whispered command but, after four decades on the road, the band know each other inside out, back to front, and every other which way you care to think of.

"I've probably spent more time with these guys than I have with my family," Petty points out.

However, the musician has said this anniversary jaunt could be The Heartbreakers' final tour - "the last big one".

"We're all on the backside of our sixties," he recently told Rolling Stone. "I don't want to spend my life on the road"

But his band don't seem too phased by the proclamation.

"I've been hearing that for 15 years," Campbell said. "We'll see."

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