Primal Scream put the "mental" back into experimental rock, so producer David Holmes didn't have to ask the veteran Scottish psych-rockers twice to try some new things on their excellent 10th album, More Light.
"There were no rules," guitarist Andrew Innes says in a thick brogue from his London home.
A former club DJ in Belfast, Holmes has spent the past 15 years composing soundtracks for films, most notably Steven Soderbergh's Ocean's Eleven series. He also mixed a couple of songs on Primal Scream's 2000 industrial rock album XTRMNTR.
Innes says the band intentionally recruited Holmes to help make a cinematic album to follow relatively "traditional" recent long-players Riot City Blues (2006) and Beautiful Future (2008).
"He knows that world and obviously with movies you've got to write something that gets in the mood of the scene rather than writing a straightforward pop song," he explains. "He wasn't so concerned with making traditional song, so that's why a lot of them are eight minutes, nine minutes and have got several sections to them."
Take, for example, River of Pain, a song that bubbles along on Middle Eastern rhythms before it suddenly transforms into something out of a big- budget, big-screen romance.
"There's sort of a dream sequence in the middle of that, or it might be a nightmare sequence, depending on how you look at it," Innes chuckles. "That was definitely from the movie world."
And like any good film, More Light features high-profile cameos - most notably one on Elimination Blues from Led Zeppelin legend Robert Plant, who lives just down the road from Primal Scream's London studio.
"Robert's a great guy and you generally bump into him at the post office," Innes says. "It's not somewhere where you'd expect to bump into one of the legends of rock'n'roll."
Yeah, it's difficult to imagine the Golden God posting a letter or buying some stamps.
"I know, you'd think he'd have a legion of minions to do these things for him," says Innes, who adds that Plant is surprisingly down-to-earth and all too keen on a chinwag at the post office or a local cafe.
The latter setting was where the great rock singer told Primal Scream frontman Bobby Gillespie that he'd be happy to contribute to More Light. "He muttered the immortal words 'I'm here till Thursday. If you need any help with your LP, you know where I am'," Innes laughs. "The light bulb went on."
The band was looking for some falsetto vocals on Elimination Blues, the female singers they had tried didn't cut the mustard and so Plant landed the role.
"He can do a high voice quite well," the guitarist deadpans. "He's done that before."
More Light also sees Primal Scream turn the poetry of San Francisco beat poet David Meltzer into the track Turn Each Other Inside Out and refashion a Jeffrey Lee Pierce (the Gun Club) demo into Goodbye Johnny.
The final track and first official single off the new album, It's Alright, It's OK, is the straightest singalong song - a reboot of 1992 hit Movin' On Up.
Primal Scream road-tested the new material during their Australian tour in December, with Innes offering high praise for the Astor Theatre where their Perth show was held.
"What a great theatre that was and it's a great place for a gig," he gushes. "If that was in England, it would have been converted into blocks of apartments."
The Scots played another impressive venue last month, namely the Royal Albert Hall as part of a Teenage Cancer Trust gala curated by Noel Gallagher.
"Honestly, when you walk on that stage, you've got some big shoes to fill," Innes says.
Primal Scream have UK and European gigs until the end of August, with Innes hoping for another Australian "holiday" when things get chilly in England.
The longest-serving member of the line-up with lone remaining founder Gillespie, Innes says Primal Scream - unlike most movie sequels - always try to improve with each outing.
"You always think your next LP will be your best one," he says. "That's the way we've always kept going because we never think we've made our best record. We always think 'We can do this better, the next one will be better'.
"This is a good one, this time," Innes says of More Light. "I'm proud of this one."