Mariah Carey accidentally stays in a hostel in ad, sings karaoke to her own song

An online travel agent is trying to shake off the dingy image of youth hostels by hiring pop singer Mariah Carey to star in a marketing campaign.

In a three-minute ad for Hostelworld, Carey arrives with a full entourage at a Barcelona hostel and finds that her assistant appears to have missed her request for a "beautifully-appointed private room in a hotel."

Standing in the lobby of the Casa Gracia hostel, she shouts at staff to "deal with it," as the entourage is shown into a dorm room.

Carey gets stuck in a lift with a topless man cleaning his teeth, before viewing a private room that meets with her approval; she is also seen in full sequins in the hostel's bar, miming to her 1995 hit "Fantasy."

"Even divas are believers" is the tagline to the ad, and a website features various "diva proof" hostels such as a Paris property with a roof terrace and a Moroccan riad guesthouse with a courtyard swimming pool.

It's not the first time Hostelworld has turned to a celebrity to get attention. In 2016, rapper 50 Cent visited a hostel's bar, shot some pool and checked out the sun terrace in another commercial for the company. Last May, comedian Phil Wang took the firm's "Speak the World" translator within its app to Indonesia to see if his jokes would make people laugh once they'd been translated. Hostelworld claims that worrying about a language barrier stops 10 percent of U.K. adults from going on vacation.

Hostelworld is an online booking company that lists 36,000 hostels around the world and made a net revenue of 86.7 million euros ($107.3 million) in 2017, an increase of 10 percent on the previous year. It listed on the London Stock Exchange in 2015.