Los Angeles, Mar 29 (IANS): Singer Mick Jagger has written his first TV theme, for the Apple TV Plus spy series 'Slow Horses', debuting April 1.

And it might never have happened if he hadn't already read and liked the Mick Herron book on which it's based, reports 'Variety'.

"It's a quite popular series of books, so I knew what it was about," the iconic Rolling Stones singer tells 'Variety'.

"I knew the vibe really well, so as soon as (composer Daniel Pemberton) sent the track to me, I just dashed off a few pages of notes of what I thought it was about. It came very, very quickly, which is always a good sign."

Pemberton, the series' Oscar-nominated composer ('The Trial of the Chicago 7'), had been working for months on the series, creating what he calls "a very unique sound world, all based on low-fi recording techniques and slightly wonky sounds".

He and Jagger didn't meet due to Covid restrictions, but in December of last year began a whirlwind series of Zoom calls, emails and text messages.

"I played him the track on guitar," Pemberton recalls.

"I'm not even a good guitarist. That was very weird, playing guitar for Mick Jagger on the Zoom line."

Adds Jagger: "I just recorded it on my iPhone and sent it to him, and he loved it. And then we had to do a bit of crafting, trying to get a chorus, calling it 'Strange Game' and trying to get the verses from the point of view of the main character," referring to Jackson Lamb, played by Gary Oldman in the series.

Lamb runs Slough House, the rundown building that is home to all of MI5's failures, all of whom are eager to redeem themselves and return to the Regent's Park headquarters as full-fledged agents. Kristin Scott Thomas, Jack Lowden, Olivia Cooke and Jonathan Pryce also star in the six-part series.

"It's quite irreverent, but the Gary Oldman character is irreverent," Jagger explains.

"It's also slightly eerie, so it combines those two things. You don't want to make it too serious."

Director James Hawes traces the need for an unusual theme song back to the start of discussions about the score in 2020.

"It is a resoundingly British show in a very confident British genre, which had to find a flavour of its own," he says.

"Right from the get-go, I thought that we could use a song in the opening to help us set the tone, particularly with the first show, which has a very dynamic, perhaps more conventional action opening. Then you have to pivot into a different sort of atmosphere, into the world of Slough House."

Hawes recalls having dinner with London music supervisor Catherine Grieves, proposing the idea of a song with "just one name in mind. I wanted somebody that felt like they were London, and had the same gravitas and swagger as Jackson Lamb. It just had to be Jagger. And I think we both laughed about it", thinking it unlikely that the veteran rocker would even consider it.

Says Grieves: "Daniel had written this brilliant opening title as an instrumental (but) which totally lent itself to a song.

The 'Slow Horses' company assembled a package to submit to Jagger's music team, including a three-and-a-half-minute trailer and a page of detail about the series by 'Slow Horses' writer Will Smith.

"We tried to distill the nature and the smell of the show, and discuss what an opening song might be," Hawes said.

"This is about the MI5 screw-ups: the ones who've left the file on the train, who slept with the wrong person, who kicked down the wrong door, and they're begging for a second chance. So it needed to be a story about people hoping for a way back to play with the big boys. That was all Mick needed."

Jagger is a perfectionist, Pemberton reports: "He wanted to make it better. I'd rework the song to accommodate his new chords…. and when he sang 'it's a strange game' in this soft mysterious voice, I went, 'that's the name of the song!' I started rearranging the song to make that the focus."

Parts of the song are heard in the body of the show. And Jagger's signature harmonica occasionally features in Pemberton's underscore.

While many TV series have licensed songs from leading rock 'n' roll stars in the past, few of Jagger's stature have written original themes. The closest comparison may be Paul McCartney's theme for "The Zoo Gang" in 1974, coincidentally also a six-part English series with an espionage backdrop.

To Hawes, the song "has a then-and-now about it that feels right. Both Mick and Gary have history that roots them in the '70s and '80s where Jackson Lamb was at his greatest strength, at the end of the Cold War. A poet like Mick could take these simple ideas of no second chances and being losers, and then conjure lyrics that give both the edge and the irony to those ideas. And he has."