Hollywood actor HEATH LEDGER spent hours seriously researching his role for new film CASANOVA - before realising it was just a comic period drama.

The A KNIGHTS TALE star, who celebrated the birth of his first child last year (05) with MICHELLE WILLIAMS, didn't realise his lothario character would be historically inaccurate.

He tells British magazine Empire, "Going into the movie I did a lot of research and read as many of Casanova's journals as I could. But when I got the script I realised that information was useless, because it's not historically correct. It's a romp. I feel like I should have sent him up more. I should have made it bigger."