'Mad Men' Le Cirque Mistake: Creator Matt Weiner Calls It 'A Terrible Error'

"Mad Men" is known for covering practically every historical event of the '60s with impressive accuracy. But on last Sunday's episode, titled "To Have And To Hold," Joan (Christina Hendricks) made a comment that immediately caught the attention of some New York City and restaurant history buffs.

In the episode, Joan and her friend Kate (Marley Shelton) discuss going to the popular restaurant Le Cirque. The only problem? Le Cirque opened in 1974, and Season 6 of "Mad Men" is set in 1968.

While a Le Cirque publicist joked to The Hollywood Reporter that the restaurant would have been open if founder Sirio Maccioni "knew Joan wanted a reservation in 1968," series creator Matt Weiner admitted the mistake was a big one.

After joking that Hendricks had “ad-libbed” the line while gathering with some of the "Mad Men" cast in New York City, he said, “No, it was a terrible error ... I think the pleasure some people get from the mistake makes more entertainment for the show.”

"Mad Men" airs on Sundays at 10 p.m. ET on AMC.