Its a very sad time at the Playboy Mansion.

Sunday evening it was announced that Hugh Hefner's secretary Mary O'Connor had passed away.

Hefner wrote on Twitter:

"Mary passed away today. We loved her more than words can say."

Known to be Hefner's confidant, friend, personal secretary and mostly as 'the rock' of the mansion, Mary began working for Hefner over 40 years ago by running the former Playboy Mansion in Chicago before moving to Los Angeles.

I first knew of her from her brief appearances on the reality show "The Girls Next Door" when Hefner's former girlfriends Holly, Bridget and Kendra would go to her office and hang out with her. (If you haven't seen the show, check it out ... one of my favorites. Loads of funny stuff, playmates and boobies.)

Rest In Peace Mary, you will be missed!!

Here is a clip from 'The Girls Next Door' when the girls head over to Mary's house to play cards and Kendra to watch the football game with Captain Bob, Mary's husband of 30 years. Definitely seemed like a down-to-earth woman ... and super funny.