Kacey Musgraves has a framed joint smoked by Willie Nelson on her wall.

The country pop star revealed the strange memento she kept from her jaunt with the 88-year-old music legend in 2014 while giving Architectural Digest a tour of her Nashville abode.

Showing the joint, she said: “That’s going to stay there unless I need to break it in case of emergency."

It turns out it wasn't just Willie who smoked the spliff.

She recalled: “He rolled this huge fatty and we all sat around and smoked it with him, and then he said, ‘Save the rest for another time,’ and I did.”

Meanwhile, the 33-year-old musician previously revealed she went on a seven-hour guided magic mushroom trip.

The ‘Rainbow’ singer was keen to process the fallout from her divorce from Ruston Kelly and to “transform [her] trauma and pain into something else” so embarked on “plant therapy”, which involved taking the hallucinogenics under supervision, an experience she found “extremely useful” but also “deeply guttural, spiritual, terrifying”.

She explained: “I did it with a doctor friend here and her husband. It’s called plant therapy.

“It’s been looked at in a lot of areas for help with depression, anxiety, addiction, so many things.

“Basically, some neuroscientists [from Baltimore’s Johns Hopkins University] have created a playlist that’s music from all over the world, put together to guide you, in that state of mind, through different emotions, feeling memories, whatever.

“We have these neural pathways that we have worn into our brain, kind of like trails in the forest, and what these plants do is basically dump six feet of snow on those pathways and allow you to form new neural connections, to change your brain, change your habits.

“Through the experience, I was blindfolded, and on a comfortable couch with a soft blanket, this music was playing and all the things I was seeing were in my mind’s eye. The music was painting this whole story, pulling from childhood memories, experiences, thoughts.

“I was feeling every pluck of a string in my body, senses start to mix, you feel colours … it’s so hard to explain.”

Kacey admitted the experience was a “big part” of creating her latest album, ‘Star-Crossed’.

She said: “The day after, you’re encouraged to journal and relisten to the playlist, triggering some of the emotions that you felt then.

“So that’s what I was doing the day after, when the word ‘Star-Crossed’ popped into my mind as a title, and the concept of a modern tragedy, the acts: the exposition, the climax and the downfall, then the resolution.

“I don’t want it to necessarily speak for my brand as a whole, but it was a big part of this process.”