Leona Lewis' third album "darker" than her previous works

The X Factor champion and Bleeding Love singer Leona Lewis says her third album, Glassheart, contains her "darkest" songs yet.

In a telephone interview from London, the 27-year-old English singer says: "The lyrics lend themselves to a darker tone, because that's the producers' style. But they're still quite empowering and they are strong songs."

The 13-track release includes collaborations with popular house act DJ Avicii, acclaimed rapper Childish Gambino and Grammy-winning record producer and songwriter Ryan Tedder.

She also roped in as executive producer Fraser T Smith, a hitmaker for artists such as Adele, Taio Cruz and James Morrison.