Miley Cyrus has hit back at criticism over her engagement, insisting "life's too short".

The 19-year-old star raised some eyebrows after announcing she is planning to marry Liam Hemsworth. Although some people may think she is too young to settle down, Miley is confident Liam is her Mr Right and she isn't rushing into anything.

"Life is too short not to be with the person you want to be with," she told the September issue of US magazine Marie Claire. "I don't really care about the wedding or the piece of paper as much as I do the promise we've made to each other. And we want to have a long engagement."

Miley also revealed some details about Liam's proposal. The Australian hunk popped the question in May with a vintage diamond ring and Miley says it was a "complete surprise".

The singer-and-actress was thrilled with Liam's choice of band, explaining it stands out from the rest of her jewellery.

"I just love that it's old and has a story... and I'm happy because it doesn't look like anything else I wear," she gushed.

Miley went on to reveal she and 22-year-old Liam are not "super-jealous" people and would never intentionally hurt one another.