Both members of the Liverpool band Her's and their tour manager have been killed in a crash in the US.
Stephen Fitzpatrick, 24, and Audun Laading, 25, and tour manager Trevor Engelbrektson, died while travelling to a gig in California on Wednesday, their record label Heist or Hit said.
The label described them as "one of the UK's most loved up and coming bands".
The duo had recently released their debut album and had been featured by BBC Introducing.
Heist Or Hit said they were killed "in a road accident in the early hours of Wednesday whilst travelling to a show in Santa Ana, California".
The former Liverpool Institute of Performing Arts (LIPA) students had performed in Phoenix, Arizona, on Tuesday and were driving about 350 miles to Santa Ana in California when the crash happened.
Posting on their Facebook page on Monday, the band wrote: "It's almost home time for the lads, US tour has gone swimmingly so far. Got a hot sunset date with the Grand Canyon tonight."
The label said: "We are all heartbroken. Their energy, vibrancy and talent came to define our label.
"As humans, they were warm, gentle and hilarious. Each time they stopped by the office made for an uplifting experience."
The Arizona Department of Public Safety said it was investigating a crash on Interstate 10 at 01:00 local time (08:00 GMT) on Wednesday, but could not confirm the identity of four people killed.
A spokesman said the release of information about the crash would be delayed as a result of "almost all evidence being lost in the fire".
"The bodies are not identifiable and we are relying on the Medical Examiner's office to help with positive identification," added the spokesman.
The band's label, Heist or Hit said Mr Fitzpatrick, from Barrow-in-Furness, Cumbria, and Mr Laading, from Norway, met for the first time in Liverpool as students.
It said the band were playing 19 shows on their second tour of North America, having released their debut album Invitation To Her's last year.
The label added: "They were in America playing to thousands of adoring fans. Fans they made a point of meeting and spending time with, such was their passion and humbleness. The world was at their feet."
Earlier this month, Her's were filmed by BBC Introducing playing an acoustic performance during the South by Southwest festival in Austin, Texas.
So sorry to hear the tragic news about Her’s. All my thoughts are with Stephen, Audun and Trevor’s family and friends at this sad time. Her’s made wonderful music, and they were the warmest people.— Huw Stephens (@huwstephens) March 29, 2019
BBC Introducing presenter Huw Stephens said the band were "excellent, funny and clearly loving playing to an American audience".
"In their interview they spoke about their enduring friendship on tour, how Liverpool had adopted them as they'd moved there from Barrow-in-Furness and Norway respectively, and their excitement about the future," he said.
"Their accomplished, joyous album released by their friends at Heist or Hit records, gained them many fans, and it will be some comfort that their music will still be enjoyed."
Fans paid tribute to the band online, including Craig MacDonald who said they were "wonderful people and fantastic musicians".
I’m in utter shock and disbelief. The world is a cruel place sometimes 😔 Stephen and Auden were wonderful people and fantastic musicians. All thoughts with their friends and family RIP x♥️♥️x— Craig MacDonald (@83Craigymac) March 28, 2019
Another fan wrote: "Such awful awful news. Always put on a great show and could tell how much they loved this music and each other. All the love to you all."
Writing about the band in 2017, music magazine NME said Her's were "not a group to stand still".
It added: "Each song they produce, from the lo-fi bedroom pop power of debut track to 'Dorothy' to the duo's equally melodic take on slacker-rock on 'Marcel', sees the Liverpool-based duo shift and float between sounds, never really fitting into one genre, but somehow nailing whatever they end up doing."
LIPA said the pair graduated from three-year degrees in music in 2016.
Head of music Martin Isherwood paid tribute to "the funniest, sweetest, loveliest, most creative lads you can ever meet".
"The songs are just great and we all thought that they were going to be one of the biggest things out of Liverpool," he added.