Robert Pattinson and Kristen Stewart will be an official couple come December, it's claimed.

The Twilight co-stars and rumoured real-life lovers are planning to go public with their – at this stage, still rumoured – relationship with an interview and photoshoot in Harper's Bazaar.

“Rob and Kristen were relatively open about their relationship,” says the magazine, according to US gossip weekly In Touch.

Rumours the pair are close off screen as well as on have been around since the release of the first Twilight movie last November.

The romance gossip has picked up in recent months after it emerged Kristen has split from actor boyfriend Michael Angarano.

Despite stories involving the pair sneaking around Los Angeles and Vancouver together - where they are currently filming Eclipse - Rob and Kristen have so far laughed off suggestions they are an item.

Rob and Kristen in pictures