Good Morning Britain viewers have expressed their dismay after hosts Piers Morgan and Susanna Reid broke the news of the Las Vegas mass shooting to an apparently oblivious Mariah Carey live on-air.

At least 50 people have been killed and over 200 injured after gunman Stephen Paddock opened fire on Route 91 Harvest country music festival from a window of Mandalay Bay Hotel and Casino.

The 48-year-old diva joined the hosts via a live link from her home as a part of a pre-booked segment. She was shown reclining on a sofa in front of a Christmas tree to promote her upcoming UK Christmas shows.

Reclining in a red gown on a chaise lounge, with a decorated Christmas tree provided an early-festive backdrop, it was obvious that Marish was prepared for a light-hearted coversation.

But Morgan quickly switched the angle of the televised interview to the Las Vegas atrocity putting Carey, who was completely unaware of the drama, on the spot.

After breaking the news live on air, he asked the Hero hitmaker − who has performed several residency shows in Las Vegas in recent years − about her instant reaction to the event that had transpired. She appeared visibly distressed.

After a pause, she replied: "It's just what everybody's gut reaction would be which is that this is horrible. I pray for the victims."

She added: "It's terrible because people are just going out to listen to music and that's what they want to do. They are out for the night and something shocking like this happens and nobody could have expected it. It's wrong, I don't really know what to say."

Viewers quickly lambasted producers for "blindsiding" the songstress and pushing forward for an "inappropriate" interview.

"Shame on @GMB using a pre-planned @MariahCarey interview to blindside her about Vegas shooting," one viewer tweeted while another added: " @GMB Terrible events in Las Vegas. Let's get the views of Mariah Carey in front of a Christmas tree! Irrelevant and inappropriate. #getagrip"

A third questioned the motives of producers, writing: "@GMB why do that to Mariah Carey! It's awkward she was expecting an interview. Make sure you get your drama gmb".

Meanwhile, Las Vegas police have tracked down Marilou Danley, the woman they wanted to speak to in association with the deadliest mass shooting in US history.

Mariah Carey
Mariah Carey appeared on Good Morning Britain in the wake of Las Vegas shooting.Angela Weiss/getty