Rumour has it that notorious ladies' man Hugh Hefner and his former fiancée Crystal Harris are revving up to say "I do".

According to scandal sheet TMZ, the Playboy mogul, 86, and Harris, 26, are engaged - again.

The couple is reportedly set to tie the knot at the Playboy mansion on New Year's Eve.

Harris and Hefner were previously engaged in December 2010 after two years together, and were to set to tie the knot in a lavish wedding at the Playboy mansion in June 2011.

But it all went south when Harris famously jilted Hef and pulled the plug on the nuptials - just five days before she was set to sashay down the aisle.

"The wedding is off," Hefner glumly told his Twitter followers at the time.

"Crystal has had a change of heart.

"The breakup is a heart breaker, but better now than after the marriage,One-Shoulder Wedding Dresses" he later added.

Multiple sources claimed that the breakup was sparked after the pair had the mother of all arguments, resulting in Harris packing her bags and hightailing it from the Playboy mansion.

Speaking after she backed out of the wedding, Harris said she felt marrying Hefner wasn't the right decision.

"I called it off because I didn't think it was the right thing for me to do," Harris said.

"After much deep reflection and thought, I have decided to end my engagement with Hef," she wrote on her official blog . "I have the utmost respect for Hef and wish him the best going forward. I hope the media will give each of us the privacy we deserve during this time."

'I HAVE NEVER SEEN HIM NAKED'

But she later gave privacy the shove by dishing the dirt on their sex life during a candid radio interview.

Probed by "shock jock" Howard Stern about their doomed relationship, Harris took a few parting shots at her former fiancé.

"Hef doesn't really take off his clothes. I have never seen him naked," said Harris, before aiming directly below the belt.simple plus size wedding dresses with short sleeves

She claimed the pair only had sex once during their relationship, and that it lasted "like about two seconds."

"Then I was just over it," she shared. "I was like, 'Ahhh.' I was over it. I just like, walked away. I'm not turned on by Hef, sorry."

Hefner said he felt like he'd dodged a bullet by not marrying Harris. "Quite frankly, I don't know what I was thinking about. I think my natural state is single. I've tried marriage twice, not successfully. These were not the happiest times of my life."

Responding to Harris' interview, Hefner took to Twitter to vent his feelings.

"We had sex once a week. We had sex with her and a girlfriend. We had sex the first night that we met, with another girl, and it was such a nice relationship that I kept them both over for a weekend,affordable one shoulder wedding dresses" he said.

He later tweeted: "I feel sorry for Crystal. She seems lost," while calling Harris a liar,high low prom dresses writing, "Crystal convinced me that she adored me. That was the first lie."

But a year later, the pair confirmed they were back together.

"Yes @hughhefner and I are back together. Yes I am his #1 girl again. Yes we are happy. Hope that clears up any confusion! xo," Harris gleefully announced in June.

Hefner also confirmed they were back on.

"It's Mary O'Conner that brought Crystal Harris back," he explained in a tweet. "Crystal was miserable and said so. Mary told Crystal to write and tell me, which she did."

He added: "Getting back together with Crystal Harris shouldn't be a big surprise, since I have a history of remaining close to former girlfriends."

Sources tell TMZ that Harris and Hef are "better than ever these days", and have "worked out all their previous problems and decided recently they want to try and get married again."

According to their insider: "Harris feels the time she spent apart from Hefner really taught her how to be independent and stand on her own two feet...something she felt she needed."

Word is the impending vow-swap will be an "intimate affair" in front of close friends and family.

According to Radar Online, Harris won't be rushing out to buy a wedding dress.Bridal Wedding Dresses The site claims that she will be wearing the same gown she bought for the first wedding.

Harris may have hinted that a wedding is on the cards last week.

Celebuzz notes that Harris took to Instagram and shared a snap of bride and groom Christmas ornaments.

"Check out these cool ornaments #mermaid #merman," she wrote.

Later adding, "Dear past, thank you for all the lessons. Dear future, I'm ready."

There's been no official comment from the couple on the rumoured nuptials.

If the lusty octogenarian really has popped the question, he must have forked out for new engagement bling. Harris famously put the orphaned $90,000 engagement sparkler Hef bought her on the auction block after their relationship went kaput.

Earlier this year, Hef said he had a firm resolution - to remain unwed.

"This year has been a very interesting year for me, I almost got married," he told People mag. "And as Holly (Madison) - a dear friend and former girlfriend - said, 'Well, you missed a bullet.'

"I think that's accurate. I am clearly not meant to be married. Married life isn't for me."