Crystal Harris is taking her grief and turning it into something good. The Playboy Playmate and Mrs. Hugh Hefner took to Twitter on Thursday, Jan. 31, to announce that she will be auctioning off her pink wedding gown to raise funds for cancer research in honor of late "Mansion Mother" Mary O'Connor.

"I am auctioning my wedding dress with @charitybuzz to raise money for lymphoma in memory of Mary," she shared with fans. Worn at her Dec. 31 wedding to Hefner, the strapless, floor-length mermaid-style Romona Keveza gown is valued at an estimated $7,500, according to the Charity Buzz website, and is currently at a bid of $1,100.

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The 26-year-old Playboy model is also auctioning off her matching Aruna Seth shoes.

Hefner, 86, was "devastated" over O'Connor's death, an insider told Us Weekly. The Playboy founder previously credited her for helping to reconcile him with Harris after the two called off their engagement in June 2011.

"It's Mary O'Conner that brought Crystal Harris back," Hefner explained on Twitter on June 1, 2012. "Crystal was miserable & said so. Mary told Crystal to write and tell me, which she did."

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O'Connor, who worked as Hefner's secretary for more than 40 years, passed away on Sunday, Jan. 29, following a "short illness," according to a statement on a Facebook page created in her honor. She was 84.

"Mary was surrounded by her brother and close friends at the time of her death," the statement read, inviting "all of Mary's loving friends from around the world" to leave messages in her honor. "Camera shy, modest, her whole life was given over to serving her friends and colleagues to whom she was fiercely loyal," the statement continued.

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Hefner's longtime assistant is survived by her brother James Feuchtinger, sister-in-law Seila and several nieces and nephews. Her husband, "Captain Bob," passed away in April 2012. 

Fans of E!'s 2008 show The Girls Next Door and Playboy models alike flooded the Internet in the days following, sharing their condolences and remembering O'Connor in a series of tweets and messages.

"Just got news that Mary was the most googled person today,” Harris tweeted on Jan. 28. “Proof of how much people care. Love you Mary!"

This article originally appeared on Crystal Harris Auctioning Off Wedding Dress From Hugh Hefner Nuptials to Raise Money in Mary O'Connor's Memory