'Entourage' star spends time with Hilton

Entourage star Adrian Grenier has been spotted spending time with Paris Hilton.

The actor, who plays Vincent Chase on the HBO show, was seen spending a day swimming with Paris last week, before they attended the premiere of Leonardo DiCaprio's new environmental documentary 11th Hour together.

A representative for Hilton denied rumours of a romance, insisting that the pair are "just friends".

Speaking to Fox News at the premiere, Paris revealed that environmental issues are important to her: "I just want to make people aware of little things like recycling and cutting the plastic off a six-pack of coke."

She also took time to praise her Simple Life co-star Nicole Richie, who she believes will be "a really great mum".