Hugh Hefner's oldest son Marston Hefner was arrested last night after he allegedly attacked his Playmate of the Year girlfriend Claire Sinclair ... TMZ has learned.

Law enforcement sources tell TMZ ... cops were called to the pad Marston shares with Sinclair in Pasadena, CA after one of Sinclair's family members called 911, claiming Marston had attacked her. 

Cops arrived to the scene ... and we're told officers observed visible injuries on Sinclair's body ... including bruises and red marks.

Law enforcement sources tell TMZ ... Marston admitted the two had gotten into an argument ... but did not cop to striking Sinclair.

Sources tell us ... Sinclair told cops Marston had punched her, kicked her in the stomach and then refused to let her leave the residence.  We're told Sinclair called family members after the alleged attack ... and her family called the cops.

After a brief investigation, Marston was arrested for misdemeanor domestic violence at around 11:15 PM ... and hauled to a nearby police station where he was booked.

Marston was released on $20,000 bail a few hours later.

20-year-old Sinclair was named PMOY in 2011. She has been dating Marston on-and-off since August 2010.

The awards aren't until Sunday, but Playboy's Miss August 2010 Francesca Frigo showed off her gorgeous golden globes in a hot pink string bikini in Miami on Tuesday.

The 25-year-old Venezuelan goddess is very, very talented.

Jessica Burciaga -- the ridiculously hot chick rumored to be Kobe Bryant's mistress -- says don't believe what you hear ... she is NOT the straw that broke Vanessa Bryant's back.

Former Playboy Playmate Jessica spoke out last night in L.A. -- responding to Internet rumors that she's been Kobe's side piece with two simple words ... "Not I."

Jessica -- Miss February 2009 (amateur researchers take note) -- was also asked about Playboy's latest covergirl ... and it's fair to say she has a less than glowing review of Lindsay Lohan's spread.

Lindsay Lohan definitely gave Playboy their money's worth ... because the issue is selling out all across the country ... TMZ has learned.

According to our sources, newsstands in major cities like New York and Los Angeles have had to re-order the issue multiple times. We're told Playboy is even getting re-orders from cities that usually never order more issues.

Our sources say Lindsay's appearance in the mag has also had an effect online as well ... where the mag has seen a huge increase in subscription sales to their online service, iPlayboy.com.

If only her movies did this well ...

Lindsay Lohan's nude Playboy spread did NOT live up to the hype ... so says someone who's DEFINITELY in a position to judge -- 2010 Playmate of the Year Hope Dworaczyk.

Hope was out in L.A. yesterday -- leaving a waxing salon called Stript Wax Bar -- when we asked about the pics ... and she replied,  "I saw that spread ... and I was not impressed."

She added, "I just feel like if I would have known I was doing a Playboy shoot, I would have worked out more maybe."

So, we gotta ask ...

Lo and behold ... the only surviving shot from the Lindsay Lohan Playboy photo shoot that hasn't been touched up by professionals ... and it might be the best one of the entire spread.

The pic was taken behind the scenes during Lindsay's 2-day shoot back in November -- right before she disrobed for a Marilyn Monroe-inspired spread.

The final shoots were leaked onto the web yesterday -- and while Lindsay looks good, it's obvious they were photoshopped like a mutha.

So, we gotta ask ...

Hugh Hefner has been screwed by the Internet .. and now the Playboy honcho has announced he's releasing the Lindsay Lohan issue early ... after the entire spread was leaked on the web.

Hef just tweeted, "Because of the interest & the Internet leak, we're releasing the Lindsay Lohan issue early."

As we previously reported, Playboy invested a TON of money into the Lohan edition -- and had printed thousands of extra copies in anticipation of unprecedented demand.

No new release date has been announced ... yet.

Lindsay Lohan's highly classified Playboy photo shoot leaked to the Internet this morning -- one week before the issues was set to hit newsstands -- and TMZ has learned Playboy honchos are "freaking out."

First off -- the pics aren't bad ... it's a Marilyn Monroe thing ... and it works.

Playboy sources tell us ... there are fears the leak could significantly damage sales of the magazine ... which is expected to be the best seller of the year.

The shoot was a massive investment for Playboy -- the mag shelled out nearly $1 million to Lohan  for the spread and we're told the company has printed thousands of extra copies in anticipation of a sales boom.

The "Leather Meets Lace" party at the Playboy Mansion has triggered a lawsuit, filed by men who allegedly had to pay for admission while "gorgeous ladies" did not.

Steve Frye is suing on behalf of all men who paid $1,000 to get into the shindig.  In his lawsuit, Frye claims he was fried when he learned "gorgeous ladies" got in free.

Frye claims the double standard is sex discrimination, pure and simple.  He also says offering these women free admission "promotes harmful, negative stereotypes."

He's suing for unspecified damages ... and a life.

Lindsay Lohan was not immediately sent to jail because the judge decided to allow her time to complete her nude photo shoot for Playboy ... TMZ has learned.

Sources directly connected with Lindsay tell us ... Lindsay's lawyer, Shawn Holley, told the judge in chambers that Lindsay had a contract with Playboy -- a contract of nearly $1 million -- and the shoot must be completed this week.  If it isn't, Lindsay would be in breach of her contract.

So Judge Stephanie Sautner cut LiLo a break ... and gave her one week to surrender.  Lindsay will surrender for the camera in the next few days.

Justice is not only blind ... sometimes it's stark naked.

Former Playboy Playmate of the Year Jayde Nicole thinks Lindsay Lohan better do something "like  nasty" to justify her almost-million dollar payday from Playboy ...  including, "spread eagle."
 
Nicole explains, "if you're getting a million dollars, I wanna see s**t I've never seen before."

Anyone wanna argue with that?