Mick Jagger used his iPhone to create the `Slow Horses` theme song
(iMore iPhone)

What you need to know Mick Jagger says he helped with the Slow Horses theme song because he liked the book it`s based on. Working with the show`s composer was hampered by COVID restrictions. Jagger ended up recording on his iPhone. Jagger says he `just recorded it` on his iPhone. The upcoming Apple TV+ show Slow Horses has Mick Jagger to thank for its theme song, but that might never have happened if the star wasn`t already a fan of the book that the show is based on. And he had to use his iPhone to get things moving. The next big thing to land on Apple TV+ later this week, Slow Horses is based on a book by the same name — and Variety reports that was one of the reasons that Jagger was happy to get involved with writing its theme tune. `It`s a quite popular series of books, so I knew what it was about,` the legendary 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 pa...