When John Lennon and Paul McCartney would sit down to write a hit song, they’d motivate each other by saying: “Let’s write a swimming pool”. Diane Warren can go one better than that.

“My songs bought a building,” she laughs. “That’s pretty fucking cool.”

She isn’t lying. The Realsongs building in Los Angeles proudly proclaims itself the home of the “Diane Warren Music Company”, while Nashville-style canvas banners promote her latest huge song, Andra Day & Common’s Stand Up For ...