The BBC recently conducted an interview with Harry Potter actor Daniel Radcliffe where he talked about filming Half-Blood Prince and what he thought of Deathly Hallows amongst other things. On how the sixth film is coming along:
“Really well. I've just been doing a bit of work with Jim Broadbent who plays Horace Slughorn, who's just fantastic. And we've been doing a bit of stuff with me and Rupert Grint. We haven't done any scenes with all the kids yet in the Great Hall – that's all to look forward to just after Christmas. It's glorious to be working with [director] David Yates again.”
Dan acknowledged he didn't read the seventh book until about four days after it came out, so he was “walking around with his fingers in his ears.” Luckily, it wasn't spoiled for him.