It’s a sad day at the typically chipper Playboy Mansion.

Hugh Hefner’s secretary of more than 40 years, Mary O’Connor, passed away.

The Playboy tycoon announced via Twitter that his beloved secretary had died on Sunday.

"Mary passed away today. We loved her more than words can say,” he wrote.

O’Connor made brief cameos on “Girls Next Door,” and all Hefner’s former girlfriends took to Twitter to share their sadness over the secretary passing.

"RIP Mary O'Connor. She was an amazing person who helped me through so much," Kendra Wilkinson-Baskett posted. "But I know she's happy with her boo Captain Bob. :)"

"Captain Bob" was O'Connor's husband, who had passed away years ago.

"Thank you for all the sweet messages," Bridget Marquardt wrote. "Mary O'Connor will be missed. #RIPMary."

Holly Madison was succinct with her condolences: "Rest In Peace Mary."

Hefner credits O’Connor with bringing his wife Crystal Harris, 26, back into the mansion after she famously left the 86-year-old at the altar.

"It's Mary O'Connor that brought Crystal Harris back," he tweeted after the couple reconciled. "Crystal was miserable & said so. Mary told Crystal to write & tell me, which she did."

Harris also took to Twitter to share her respects over O’Connor passing.

"Hef's long time secretary & my dear friend Mary O'Connor has passed away," she wrote. "It's a very sad day here at the Playboy Mansion. We love you Mary."

Marquardt, one of the stars from the “Girls Next Door,” opened up about the secretary who was reportedly in her 80s.

She told Hollywood Life:

“Mary was a confidant that you could always count on. I could vent to her, and she would listen, but even more than that she always had a solution for whatever was bothering me. Mary was instrumental at the Mansion in so many ways. I can’t even imagine what life will be like there without her.”

According to TMZ, O'Connor had been dealing with health problems recently and a source told the website she was “the rock” of the mansion and everyone in the house is “incredibly sad.”