Mariah Carey. Picture: AP

Mariah Carey is ready to bare her soul in her new music and says the album will be a mix of "light-hearted" and "deep" emotions.

The 48-year-old singer - who has announced plans to extend her Las Vegas residency 'The Butterfly Returns' into 2019 - is currently working on new music and says it will cover the whole range of emotions she has been feeling.

She told PEOPLE: "I've been working on my new album for a while. This is a labour of love and I'm really excited. This is me at this moment in my life being able to express myself as a writer and a singer. I'm just really in a good place.

"My fans just want to hear me express myself and speak from the heart and sing from the heart. Some of the record is lighthearted and fun, and some [songs] I really went deep in terms of the lyrical content. There's a nice cross-section of things."

Mariah is also excited about changing up the setlist of her residency to surprise her fans.

She said: "I've been loving it so much. A lot of the fans who have come out to see it were really happy having a little more diversity. I want to make it really impromptu and surprise the people who have come out again and again to see the show."

Mariah's 'Butterfly Returns' Las Vegas residency shows, opened at The Colosseum at Caesars Palace in July and was originally set to finish in September.

However, she has now added five new dates in February for her fans. 

Meanwhile, Mariah previously revealed she is thrilled to be back in the recording studio.

She said: "It's really nice writing and collaborating. Writing is the best part of the process.

"Most people may love performing more - I'm not saying I don't - but I love being in the lab and working on new material and pouring my heart into it."

Watch Mariah Carey's 90s hit song "Emotions" below.