TORONTO - It turns out even the Beatles are "Mad Men" devotees.

Sunday's episode of the acclaimed drama ended with brooding ad man Don Draper alone in his New York City apartment listening to "Tomorrow Never Knows" from the Fab Four's 1966 album "Revolver."

"Mad Men" husband-and-wife writing-producing duo Andre and Maria Jacquemetton say the show's creative team desperately wanted that particular song.

"In the case of the Beatles, they're not known for opening up their song catalogue to everyone," Andre Jacquemetton said Monday.

"It just turns out actually that they're huge fans of the show. So in a way, it's 'who do you get to talk to?"'

Added Maria Jacquemetton: "It was really ('Mad Men' creator) Matt Weiner making a personal appeal, he really worked very hard to get that particular song in the episode."

In the instalment, entitled "Lady Lazarus," Draper's wife Megan (Jessica Pare) announces plans to quit the advertising business to resume pursuit of an acting career. She gives her husband the album after it's revealed he knows woefully little about popular music.

"(Weiner) and the writers felt very strongly that that was sort of a seminal song and moment in music history and that we really wanted it to be in that episode," said Maria Jacquemetton.

"The episode is so much about Don's disappointment over the woman that he loves not wanting to be at his side and his creative partner anymore ... and him sort of feeling out of touch with everything that's going on around him."

That has been a recurring theme this season as the straitlaced Draper deals with the advent of the psychedelic 1960s. It was a cultural shift touched on in an episode a couple of weeks ago when Draper's colleague, Roger Sterling, went on an acid trip.

"We knew we wanted someone to take LSD and we'd wanted someone to take LSD for a couple of seasons now," said Maria Jacquemetton.

"It's just timing-wise, chronologically and storywise in terms of where everyone's characters were, it hadn't been right until that episode."

She says there was much debate over which character would experiment with the mind-altering drug.

"We discussed, you know, who would be the likely character to do it. There was some feeling that (senior ad exec) Bert Cooper would have already done it because of his, you know..."

".... Worldly ways," said Andre Jacquemetton, laughingly finishing her sentence.

Added Maria: "We discussed whether or not Don would do it and decided that Don is an open person ... and he probably would but in the end, the person's whose story seemed to fit the mind-opening experience the best was Roger."

Summed up Andre: "I think we ended up going with Roger because it was the most fun.There was going to be comedic possibilities there. It was an unusual direction to go."

Although the show is dissected endlessly by fans online, the pair says they largely ignore the recaps.

"For the most part it's just too overwhelming for us and there's nothing we can do about it," said Andre Jacquemetton. "People are going to interpret the show the way they're going to interpret it."

Although the writers and producers of "Mad Men" are famously tight-lipped about what lies ahead for the characters, it seems clear there's more angst ahead for Draper.

"You really get the sense in last night's episode that Don is old," said Andre Jacquemetton.

"And that time is moving much quicker than he would like it to be."

Of Weiner's relentless quest to get the rights Beatles song, he added: "It took a long time, he had to speak to quite a few people and write some letters, but it got done. And was it amazing."

The Jacquemettons were in Toronto to give a master class at the Canadian Film Centre. They were scheduled to speak at the Bell Lightbox later in the day.