British actor Dominic Monaghan is refusing to comment on the nature of his relationship with his Lost co-star Evangeline Lilly, but promises he plans never to be photographed at a celebrity event with her again.

Monaghan describes his relationship with Lilly as "unique", but will not be drawn into confirming she's his girlfriend.

He says, "We kind of understand where each other's going, and we're good friends. She's a beautiful girl.

"And then everyone's asking if we're dating. I think our relationship is unique because we're a similar age, and we're kind of interested in the same things.

"But I'm never going to get photographed with her again."