Lindsay Lohan, John Mayer, Willie Nelson and Justin Bieber all got a David Letterman mocking during his Top 10 Surprises at the Grammy Awards Sunday night.

No. 10 “Lindsay Lohan seen leaving the Staples Center with a Grammy-shaped bulge,” he joked. The actress is currently free on bail with a felony grand theft charge.

No. 9: “New music laws prohibit rhyming ladies with Mercedes.”

No 8: “Willie Nelson provided the Grammy show snacks.” Nelson was arrested in November for pot possession.

No. 7: “Jay-Z revealed ‘Empire State of Mind’ was really about Trenton, New Jersey.”

No. 6: “The new category: best male or female traditional R&B urban alternative non classic latin performance by a duo or group with vocals.”

No. 5: “In a touching ceremony, will.i.am added a comma.” The Black Eyed Peas member laughed at the joke when cameras panned to him after.

No. 4: “The Academy president finally explains the difference between record of the year and song of the year.”

No. 3: “Lady Antebullum and Lady Gaga form supergroup Lady Antegagum.”

No. 2: “John Mayer caught in a passionate embrace with Susan Boyle.”

And No. 1 “Justin Bieber? Hair piece.”

Justin Bieber seemed to miss the joke when cameras panned to him, but his buddy Usher laughed.

So we all know the Joaquin Phoenix whackness was fake, but the big question this week has been was David Letterman in on the joke when he interviewed Joaquin’s alter-ego last year.

Joaquin appeared on The Late Show with David Letterman Wednesday night to clear the air and to apologize to Letterman for pulling the wool over his eyes.

“You’ve interviewed many, many people and I assumed that you would know the difference between a character and a real person, so – but I apologize,” Phoenix said. “I hope I didn’t offend you in any way.”

Phoenix was clean-cut and shaven Wednesday, without the shaggy beard, unruly hair and sunglasses he wore on Feb. 11, 2009, when he told a befuddled Letterman that he was giving up acting for a rap career. Describing that appearance on Wednesday, Letterman said it was “like you slipped and hit your head in the tub.”

At Letterman’s urging, Phoenix made clear that the talk-show host was not in on the joke. “We’d hoped to come on a talk show,” Phoenix said with a laugh, “and I was looking for a beat down, and I got one … I want to thank you for that.”

On another interesting note; Casey Affleck, the filmaker, told Jay Leno on the “Tonight” show Tuesday, that no one from Hollywood called to express concern about Phoenix when he was acting strangely. “Afterward, the movie comes out, the critics like to say `this is crazy, this is disturbing, this is sick,’” he said. “But while it’s happening, people were happy just to mock him and make fun of him.”

Better than never. On an episode that will air this Friday, Nicole Richie will announce her engagement to long time boyfriend (and baby-daddy) Joel Madden.

Richie, 28, and Madden, 30, have been planning their wedding before the birth of daughter Harlow in 2007. Apparently with the birth of son Sparrow last September, the couple figured it was time to ramp things up.

Kiefer Sutherland’s faith in Tom Brady and the New England Patriots resulted in him wearing a green dress and combat boots on the David Letterman show last night. The “24″ star told Dave that he lost a bet that New England would beat Baltimore over the weekend.

Dave’s first comment, when he stopped laughing, was, “You doing a remake of Beverly Hillbillies? You’re Granny?” He followed up with an offer, “If you get on the subway like that, I’ll give you $1,000.”

Kiefer responded, “Riding the subway would be easier than what I’m going through right now. This I think might be the most humiliating moment of life, and I’ve had a few to choose from.”

Kiefer has been arrested for DUI,  he’s been filmed drunk on numerous occasions and then there’s this video where he bounces off a Christmas tree.

Here’s a tip to anyone getting their swerve on after hours at the office/studio. Make sure you know where the surveillance cameras are and avoid them like the plague.

David Letterman owned up to cheating on his wife with a co-worker in the most dignified and mature way, but his public apologies and embarrassment might not be enough to get him off the hook. Because now…there is a TAPE. It’s one thing for everyone to know he boinked a young co-worker..quite another for everyone to SEE it.

A studio surveillance tape reportedly caught the 62-year-old star and a much-younger female co-worker in a compromising position – and it could shatter Letterman’s already troubled marriage, say sources. What’s more, the tape could persuade worried CBS execs to hammer the final nail into the talk-show host’s late-night career – and could play a key role in the trial of the producer who allegedly tried to blackmail him.

“If the tape makes its way into the criminal case, it’ll explode his marriage to smithereens,” revealed a close source. “Dave apparently didn’t know the location of the security cameras at his Late Show studio.”

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