The story behind "The King's Speech"

Scott Pelley also interviews the film's Oscar-winning star Colin Firth

His grandfather's diaries were up in the attic in boxes that the family had nearly forgotten. When Logue hauled them down for the movie, he discovered more than 100 letters between the therapist and his king.

"'My dear Logue, thank you so much for sending me the books for my birthday, which are most acceptable.' That's so British isn't it. 'Yours very sincerely, Albert,'" Logue read from one of the letters.

"As you read through all these letters between your grandfather and the king, what did it tell you about the relationship between these two men?" Pelley asked.

"It's not the relationship between a doctor and his patient, it's a relationship between friends," Logue said.

We met Logue at the same address where his grandfather treated the king. And among the hundreds of pages of documents were Logue's first observations of George VI.

"Probably the most startling thing was the king's appointment card," Logue told Pelley. "It described in detail the king's stammer, which we hadn't seen anywhere else. And it also described in detail the intensity with the appointments."

The king saw Lionel Logue every day for an hour, including weekends.

"You know, he was so committed. I think he decided 'This is it. I have to overcome this stammer, and this is my chance,'" Mark Logue told Pelley.

In the film, the king throws himself into crazy therapies. But in truth, Logue didn't record his methods. The scenes are based on Seidler's experience and ideas of the actors.

"We threw in stuff that we knew. I mean, somebody had told me that the only way to release that muscle," actor Geoffrey Rush said of one of the speech exercises he did in the movie. "And of course, little did I realize that the particular lens they were using on that shot made me look like a Galapagos tortoise."

While the treatments spring from imagination, the actors read Logue's diaries and letters to bring realism to everything else.

"The line at the end, I found reading the diaries in bed one night, 'cause this is what I used to do every night, when Logue says 'You still stammered on the 'W'," Firth said.

The line was used in the movie.

"It shows that these men had a sense of humor. It showed that there was wit. It showed there was self mockery and it just showed a kind of buoyancy of spirit between them. The fact that he spoke on a desk standing upright in this little hidden room is something we found in the diaries as well," Firth told Pelley.

"In reality he had to stand up to speak, he had to have the window open," Firth said. "And he had to have his jacket off."

"And that wonderful, specific little eccentric observation that came from reality," Firth added.

One of the most remarkable things to come out of the Logue attic was a copy of what maybe the most important speech the king ever made - the speech that gave the movie its name. This was the moment when King George VI had to tell his people that for the second time in a generation they were at war with Germany. The stakes were enormous. The leader of the empire could not stumble over these words.