Shawn Mendes made an emotional return to the stage in London on Tuesday, two years after scrapping a world tour to focus on his mental health.

The pop star played an intimate show at the Theatre Royal Drury Lane in London, previewing his new album to a room full of dedicated fans.

The show was punctuated by screams of "we love you, Shawn", as he talked at length about the struggles he'd faced in the last two years.

The 26-year-old recalled cancelling his 2022 tour after just seven shows, telling fans: "I got back to LA and I was like, 'I have no idea who I am and what to do with myself'."

"I was not really singing, I was not really playing guitar," he added, saying he had only written "one song" in the year afterwards.

That song, a hushed balled called Who I Am, will open his new album, Shawn, when it is released in October.

As heard in London, it gave a candid account of his state of mind in 2022.

"I feel pressured by the people I love," he sang over a finger-plucked guitar. "I'm losing myself trying to make you proud. Sorry, got to do it, got to let you down."

Introducing another song, Heavy, the Canadian star talked about the intense feelings of loneliness and anxiety he'd experienced after hits like Stitches and Senorita catapulted him to worldwide fame.

"The thing that was so terrifying for me was this sensation of being alone... in a situation where it was all on my shoulders," he said.

"It gets heavy when it’s all on your shoulders [but] these days I’m starting to realise there’s a lot of people I can fall back on."

He also joked about the period where he "grew out his beard" and walked around Los Angeles wearing the same tracksuit for days on end, only to be snapped by paparazzi.

"There were all these crazy articles [about] me joining a cult and me joining a wizard society," Mendes laughed, while admitting he had "tried mushrooms" to gain new perspectives on his life.

The new material introduced a more mature, rootsy sound for 26-year-old, whose nimble acoustic guitar playing was supplemented by double bass, mandolin and violin.

Despite his previous struggles, he seemed relaxed on stage, surrounded by a close-knit band of musicians, who gathered in a semi-circle around him to sing harmonies.

Fans, who’d been waiting since 2019 to see Mendes play in the UK, showed their support with a foot-stomping singalong to the new single Why Why Why, which shook the floorboards of the theatre.

And when Mendes sang the lyric "If I call tonight will you pick up", during the song In Between, one audience member responded with an emphatic, "YES!"

He ended the show with a cover of Leonard Cohen's Hallelujah, which he played on a harmonium - an instrument that he said had helped him "fall back in love" with singing during his year in the wilderness.

As the song drew to a close, Mendes talked about the hours he had spent alone, playing the harmonium and "free singing", just to feel the joy of making music without the pressure of writing hits.

He asked permission to try it out in front of the London audience, before drifting into a wordless, intimate melisma.

It was an unusual, almost eerie way to end a showcase of new material - but one that felt appropriate for Mendes' desire to feel as happy on stage as his fans are watching him.