Daniel Radcliffe romancing Kill Your Darlings co-star - report

Daniel Radcliffe has sparked new romance rumors after flirting with his Kill Your Darlings co-star at the Sundance Film Festival in Utah on Friday night (18Jan13).

The Harry Potter star was spotted cuddling actress Erin Darke at a Gray Goose Blue Door event in Park City, where they partied with castmate Michael C. Hall and his novelist girlfriend, Morgan Macgregor.

According to onlookers, Radcliffe was affectionate with Darke throughout the night and they even shared a kiss, before huddling together outside the venue later in the evening.

Radcliffe dodged questions about a blossoming relationship, telling People.com, "Erin? Oh, Erin Darke? Yeah, the whole cast is here. It's fantastic," while an insider tells the publication, "They've been dating for a while but have been debating going public."

Radcliffe, who plays beat poet Allen Ginsberg in Kill Your Darlings, has previously dated actress Laura O'Toole and production assistant Rosie Coker, who he split from last year (12).