David Hasselhoff and his girlfriend put aside whatever differences led to their blowout fight Saturday night in Las Vegas -- because not long after security was called to their room ... they hosted a party!


As TMZ first reported, the Hoff and GF Hayley got into it in their hotel room at the Wynn ... to the point where Hayley called for security. 

But the couple put on their best face and made their way down to Blush ... where the Hoff celebrated his 59th birthday ... as if nothing ever happened.

Earlier in the day, Hoff and Hayley hung out by the pool where he put on his "Baywatch" best, much to the delight of the crowd.

TMZ has learned ... David Hasselhoff had some sort of blow-out argument with his girlfriend in Las Vegas Saturday night ... and it got so heated hotel security had to come to the rescue.

Hasselhoff was at the Wynn to celebrate his 59th birthday.  His friends were throwing the bash for him at Blush, inside the hotel.

But early this evening, Hasselhoff's girlfriend called for security and one source says she appeared to have been in some sort of distress.

Security came ... and for a while there was some question as to whether David would make it to his own party,  But now we're told David will indeed show up -- he's scheduled to walk the red carpet with his girlfriend at 11 PM.

Stay tuned.

"Baywatch" grandaddy David Hasselhoff can still rock those red trunks.



Here's the TV  lifeguard back in his '90s heyday (left) -- and the 58-year-old on the set of "Piranha 3DD" in North Carolina on Friday (right).

Someone's been laying off the cheeseburgers.

David Hasselhoff NEVER starred in "Baywatch" ... and if you ask him what he does for a living, he'll tell you he's a power tech from Texas ... but here's the craziest part -- he ain't lying.


Here's the deal -- the bald guy who ate at Geisha House in Hollywood last night is ALSO named David Hasselhoff ... but he's a power technician from Texas.

Turns out ... Bald Hoff and German pop star Hoff are switching lives for a new CBS reality show -- in which celebs trade places with normal people who happen to share the same name.

So while this Hoff is living in the "Baywatch" star's L.A. mansion and eating at fancy restaurants ... the Knight Rider Hoff is trudging around Texas somewhere, probably getting electrocuted.

While David Hasselhoff is facing off in this season's "Dancing with the Stars" -- take a trip down memory lane and watch his tantric talent grow as the years fly by!

TMZ is blowing the lid off of the "Dancing with the Stars" premiere -- 'cause we know EVERY SINGLE THING that's set to go down on the show ... from songs to props and even EXPLOSIONS!


BTW -- SPOILER ALERT follows:

The most shocking performance -- Bristol Palin and Mark Ballas -- they Cha-Cha to "Mama Told Me (Not to Come)" ... are you listening Levi?  But the best part -- Bristol will rip off some "tear-away clothes" while Sarah Palin sits in the audience! 

David Hasselhoff will also be dropping a "Sex Bomb" of his own -- Tom Jones style -- complete with sunglasses and a pyrotechnics.

Here's how it will break down ...

-- Audrina Patridge and Tony Dovolani -- Cha-Cha -- "California Gurls"

-- Bristol Palin and Mark Ballas -- Cha-Cha --  "Mama Told Me (Not to Come)"

-- Margaret Cho and Louis Van Amstel -- Viennese Waltz --  "We are the Champions"

-- Jennifer Grey and Derek Hough -- Viennese Waltz -- "These Arms of Mine"

-- Florence Henderson and Corky Ballas -- Cha-Cha -- "Kiss Me Honey Honey Kiss Me"

-- Brandy and Maks Chmerkovskiy -- Viennese Waltz -- "Cry Me Out"

-- Kurt Warner and Anna Trebunskaya -- Viennese Waltz -- "This Ain't a Love Song"

--Kyle Massey and Lacey Schwimmer -- Cha-Cha -- "My First Kiss"

-- Rick Fox and Cheryl Burke -- Viennese Waltz -- "Crazy"

-- David Hasselhoff and Kym Johnson -- Cha-Cha -- "Sex Bomb"

-- Michael Bolton and Chelsie Hightower -- Viennese Waltz -- "Life After You"

-- The Situation and Karina Smirnoff -- Cha-Cha -- "Break Your Heart"

We took your questions on everything -- including Paris Hilton's BF pulling a gun on an alleged intruder, Leonardo DiCaprio's "delusional" stalker, and Michael Jackson's kids going to a private school.


Plus: Mel Gibson and Oksana Grigorieva cases.

Gilbert Gottfried claims some of his best material got cut from the "Comedy Central Roast of David Hasselhoff" -- but last night in NY, dude put the crosshairs right back on fellow roaster Lisa Lampanelli ... and fired off a few rounds of comedy gold.

** WARNING -- THIS IS PRETTY RACY STUFF **

Comedian Whitney Cummings claims she's "not a horrible person" -- despite the barrage of insults she hurled at Comedy Central's Roast of David Hasselhoff ... though she may have one regret. 


As you may remember -- Cummings sent jaws to the floor at The Hoff's Roast when she suggested that Hulk Hogan's daughter Brooke, along with Pam Anderson, should both drink a "vat of Magic Johnson's blood."

But last night outside Sam Tripoli's Naughty Night at the Improv on Melrose -- she admitted, "I did say some things about [Hulk's] daughter that weren't necessary ... but I don't think I was the meanest."

Cummings -- who has a Comedy Central special of her own on the way -- also noted, "It's a Roast ... the idea is to be edgy and mean."

He was called an alcoholic ... a disgrace ... a disaster -- but David Hasselhoff claims he has no hard feelings from Sunday night's Comedy Central Roast ... telling us, "No one laughed harder than me!"


Hoff -- whose liver was described as being "so black and bloated, it could've starred in 'Precious'" -- made his triumphant return to L.A. last night.

During our convo, it sounded like his speech was a little slurred after the long flight from Biloxi -- but we're hoping it's just because he was tired. 

TMZ has learned legendary humiliator Lisa Lampanelli will be returning from her "Roast"  hiatus to burn David Hasselhoff at the upcoming Comedy Central special.



Of course, the Queen of Mean was M.I.A. at last year's Joan Rivers roast because she claimed it was "not worth doing if I ain't roastmaster."

But now, sources close to the insult hurler tell us Lampanelli has worked out a pretty sweet deal with the network and will be taping promos for the show later today.

As for what influenced her decision -- we're told it all has to do with, "Great money, a great spot" and "other things that made it worth her while."