Miley Cyrus has opened up about fiance Liam Hemsworth's romantic spontaneous proposal.

The 19-year-old 'Can't Be Tamed' singer - who got engaged to the 22-year-old 'The Hunger Games' actor last June - revealed he popped the question after she treated him to an intimate performance of one of his favourite songs 'Look What They've Done To My Song' by Melanie Safka in their backyard.

Miley told 'The Tonight Show With Jay Leno' last night (12.10.12): ''About twenty minutes after that song - that's one of Liam's favourite songs - he asked me to marry him, like, twenty minutes later so while I was singing that I had no idea and he's sitting there and I'm like he's looking at me funny and then I know.''

Liam recently demonstrated his commitment to Miley by getting a similar tattoo as her from President Roosevelt's famous 'Citizenship in a Republic' speech made in 1910.

The loved-up couple - who met on the set of 'The Last Song' in 2010 - are in no rush to walk down the aisle.

'The Climb' singer said: ''I'm really excited to obviously get married, but I kind of already feel married.

''I know we are forever. I don't really need the paper right now.''