Miley Cyrus and Liam Hemsworth reportedly acted like ''strangers'' at the 'Paranoia' premiere last night (08.07.13).

The couple - who got engaged last summer - haven't been seen together at a red carpet event in over a year, but despite their attempts to play down speculation their romance is on the rocks, they kept their distance from each other at the debut of Liam's movie in Los Angeles.

A source told Us Weekly magazine: ''Miley and Liam acted like they didn't even know each other the entire night.

''She was wearing her ring but they acted as if they were strangers.''

The 'We Can't Stop' hitmaker attempted to cosy up to the 23-year-old actor by giving him a few quick kisses, but he reportedly didn't appear too excited by them.

The source explained: ''They [the kisses] were awkward and he didn't seem into them.''

Liam also refused to answer any questions about his lover, insisting he keeps his private life to himself.

He said: ''I don't share anything personal. I try to keep as much of my personal life to myself. I don't feel the need to go out and show the world what's happening in my life every second.''