The 'Bleeding Love' singer is concerned for the future of the planet and believes it will only be saved when occupied by other 'life forms'.
She told The Sun newspaper: 'We've done so much damage I worry the world will have to end and start again.
'It will be the next people who occupy the planet who will learn from our mistakes. People are too selfish to stop the things that have caused global warming now.
'But the universe is too big for us to be the only life forms.'
The vegetarian singer – who performs 'I See You', the theme song from new blockbuster science fiction movie 'Avatar' – hopes to meet an extra-terrestrial, especially if they are like the otherworldly Na'vi who appear in James Cameron's movie.
She added: 'I hope aliens are like the Na'vi. I really like them.
'They care about the things I'm passionate about – nature, the planet, the environment.
'This song required a powerful performance so I had to find an emotional connection. I found one to them.'
Leona is not the only star who believes in aliens.
Robbie Williams is fanatical about extra-terrestrials and regularly takes late night trips in the hope of spotting UFOs.
The 'Angels' hitmaker claims to have had three close encounters of the third kind over the years and believes in ghosts.
He said: "People will think I'm mental - which I am!"