Zac Efron On Rumoured GF Halston Sage: "She's A Sweetheart"

Zac Efron and Bad Neighbours co-star Halston Sage are doing little to dispel rumours of a possible romance after cosying up together at the Los Angeles premiere of their new flick this week.

The pair - who are thought to have started dating on the set of the comedy - posed for snaps together at the event, with Efron even telling press that the blonde babe is "a sweetheart".

While the hunky actor didn't confirm he was dating Sage, Access Hollywood have quoted him as saying: "She’s really sweet. She’s a sweetheart."

The 26-year old then asked Access: "Did you talk to her? What did she say about me?”

And, Halston had nothing but good things to say about Zac, adding to the website: "It was great, he’s a really talented actor, so he made it easy."

When quizzed further about THOSE dating rumours, Sage dodged the question and replied: "Everyone… We all stay in touch. It’s so good, that’s why we’re so excited to be here because we all got so close over filming."

Meanwhile, Zac was also asked by Good Morning Britain's Richard Arnold whether he was off the market, to which the actor cheekily hit back: "I'm not really sure I'm in the market, I'm not investing."

In the same interview, Efron also revealed that he is feeling "better than ever" following his recent stints in rehab: "(I'm) better than ever now... I'm just super-excited about the future man…

"This has been a long time coming and I was a kid when I started doing this (acting), I never thought I'd have the chance to work with Seth (Rogen) so I'm pinching myself I'm still around."

Bad Neighbours - which also stars Seth Rogen and Dave Franco - is due for release on May 3.