The Hollywood stars - who have previously starred opposite one another in 'Bram Stoker's Dracula' and 'A Scanner Darkly' - have just finished filming for the upcoming romantic comedy 'Destination Wedding' and have admitted they've always had a playful soft spot for one another - even though Winona has been dating Scott Mackinlay Hahn since 2011.
Speaking during a joint interview with 'Entertainment Tonight', the 46-year-old actress said: ''I had a pretty big healthy crush on him.''
Keanu replied: ''I had a big healthy crush on you too.''
When asked what happened to those crushes, Winona said: ''Oh, it's still raging.''
Keanu added: ''They're still there.''
Their flirty admission came just hours after Winona claimed the pair actually tied the knot for real in 1992 while filming 'Dracula' in Romania together.
She said recently: ''We actually got married in Dracula. No, I swear to god I think we're married in real life.
''In that scene, Francis [Ford Coppola] used a real Romanian priest. We shot the master and he did the whole thing. So I think we're married.''
When Keanu joked: ''It's lovely to see you again'' and added: ''We said yes?'', Winona, reminded him: ''Don't you remember that? It was on Valentine's Day.''
And Keanu went on to conclude: ''Oh my gosh, we're married.''
Meanwhile, Winona has admitted she'd love to tie the knot one day.
She said: ''It would be nice.
''When you come out of this film you think about things like that, and if you don't think it can be possible or won't then maybe this one will change that perspective, like, 'Oh, this can happen. I can connect with someone like this.' ''