Eva made the comments about her other half while attending an event in Los Angeles this week.
A reporter for E! News asked her about Ryan's directoral debut, How to catch a Monster, in which she appears.
She replied: "It's basically a dark fairy tale, and I play a woman named Cat. It's a beautiful, beautiful film."
'(Ryan) really created the most beautiful, collaborative, creative atmosphere on set," she enthused, adding: "I know I'm biased. He's the best, he's the best."
Reports abounded that the pair had gone their separate ways, with some stories even stating that Ryan was on the verge of getting back together with his old flame Rachel McAdams.
Ryan and Eva haven't been photographed together this year, though the Gangster Squad actor was spotted leaving Eva's home last month.
The Hollywood stars have been dating since 2011 after meeting on the set of The Place Beyond The Pines.