No that's wrong JW. Hammil found out when he had to rehearse beofre filming. When he was told he thought that Vader was lying to tempt Luke away and that's the same reaction that James Earl Jones had.
One of the issues of SW magazine (uk) has an interview with Irvin Kershner and he says he didn't tell Mark Hammil until just before filming because he thought it would effect how he played the part.
He also praised Hammils acting in those scenes because he was dangling from the end of the platform, with strong fans blowing wind in his face and he couldn't hear what David Prowse was saying.
Um, so he was told or wasn't.???
I'm referencing a video interview with Mark, he said he had no idea. That may well mean he was told later that Vader was lying. But as Prowse also said, those lines never came up during filming so Mark would not need to be told Vader was lying unless he was lying about killing Han and/or Leia..
And I'm sure it was difficult to do that scene too. I can just imagine.
Nope. During the end battle Luke says "he told me enough, he told me you killed him". It's obvious from this line that Vader was talking about how Obi-Wan lied about his father.
Then you have the end where Luke is saying to himself "Ben, why didn't you tell me". It's all about Vader being his father.
Like I said. those lines were added after filming. In editing and what they call looping.
They shot the film out of order so the fight could have been at any time. THe actors didnt get full copys of the script, just the parts they were in.
And like I said before David Prowse also said he didnt say those lines so Mark wouldnt have necessarly know that. ANd yes. His lips arent synced all the time. Watch that scene again