The 2016 ‘Doctor Strange’ soundtrack is the latest in a history of connections.

The latest Marvel adventure, Doctor Strange, doesn’t hit the U.S. box office until later this week but has already become a smash hit overseas with an $86 million opening weekend.

And there’s still a lot of mystery about the film. Earlier this month, Doctor Strange director Scott Derrickson held a Reddit AMA and when they asked which Bob Dylan song he would have liked to use in the movie, Derrickson replied that, even though he couldn’t find a place for a Dylan song, he managed to pull off a ‘60s Pink Floyd appearance.

The homage is fitting because there’s been a long history of Doctor Strange references in Pink Floyd’s discography.

The cover art for 1968’s A Saucerful Of Secrets, the very first ever made by legendary design team Hipgnosis, was an enigmatic combination of various cryptic visuals, including a panel from the comic itself.

The following year, while working on the soundtrack to Barbet Schroeder’s film More, Pink Floyd bassist Roger Waters penned the lyrics to “Cymbaline”, a smooth song describing a nightmare. The dreamy images depicted on the song’s lyrics include a direct reference to Steven Strange.

In 1969, Pink Floyd’s third album Ummagumma featured the Saucerful of Secrets cover art buried deep in its background. So, technically, that’s another Pink Floyd album from the ‘60s on which Doctor Strange appears. And it’s a double-LP!

A few weeks back, Derrickson tweeted a still from the movie, accompanied with a quote from the 1968 song off Saucerful Of Secrets titled “Let There Be More Light”.

In the end, though, the Pink Floyd song featured in the movie is none other than “Interstellar Overdrive”. This fully instrumental, highly improvised track was the centerpiece of Pink Floyd’s earliest shows, with creative wunderkind Syd Barrett at the wheel, and remains a staple of late-sixties London psychedelic underground music.

Benedict Cumberbatch, who portrays Doctor Strange in the upcoming film, was invited on stage a few weeks ago by Pink Floyd guitarist David Gilmour to sing the lead vocals to Floyd-fan-favorite “Comfortably Numb”.