Lindsay Lohan stuck to her guns this weekend at Coachella ... telling TMZ, she followed through on her promise NOT to take a sip of booze the entire weekend -- AND WHY WOULD SHE LIE????

Lindsay was out in Malibu earlier today when we asked if she stayed clean as a whistle at the booze-filled drug-infested music festival?

We also asked about her favorite Coachella act ... and what her favorite non-alcoholic drink is? She actually answers.

Lindsay's scheduled to kick off her 90-day rehab stint on May 2nd.

Lindsay Lohan insists she was clean as a whistle at Coachella ... navigating around the muddy waters of drugs and booze.

LiLo is telling friends ... she didn't drink an ounce of alcohol and stayed clear of all drugs ... even though people all around her were getting high.

So why should we believe her, because frequently we don't?  Here's the thing.  There are NO pics that have surfaced of Lindsay partying, and whenever she does ... something gets out.

In fact ... we know Lindsay was invited to numerous parties and we checked with people who attended -- and could remember -- and no one saw her.

Lindsay is telling her friends she turned in by 10 PM both nights during the weekend.

Raising the question ... why bother going?

Clint Eastwood significantly raised the median age in Indio, CA when he hit up a water gun carnival game at the A|X Armani Exchange Neon Carnival during Coachella this weekend.

Go ahead, win me a stuffed animal.

Coachella Music Festival concert goers are too cool for school ... except when it comes to Edward Cullen and Bella Swan.

While at the annual hipster fest in the California desert this weekend, Robert Pattinson and Kristen Stewart tried to blend in with their fellow American Apparel clad music lovers ... but got chased down by a secret legion of closet "Twilight" fans.

Spending over $350 to melt in the sweltering heat for three days can cause people to do some really crazy things.

Never one to let a little thing like an impending trip to rehab get in her way, Lindsay Lohan descended upon Indio, CA last night with her brother to hit up the Coachella Valley Music and Arts Festival.

As TMZ first reported, LiLo has been swearing to friends that despite the numerous temptations Coachella brings ... she plans to stay completely clean throughout the weekend.

Time will tell ...

The Coachella Music Festival is drawing celebrities to the desert in Indio, California like a hipster journey to Mecca!

But just because you can't paint your face and aimlessly roam the open polo fields with feathers in your hair for the three-day corporate mess-tival ... it doesn't mean you can't stare at the stars who have stretched their neck out and made the trip throughout its 14-year history. 

Lindsay Lohan is going on her yearly pilgrimage to a place where drugs and alcohol are as plentiful as Botox in Bev Hills ... but she SWEARS she'll stay clean.

Lindsay is telling friends ... she doesn't care about all the snipers who are scoffing at the recidivist rehabber -- she says she's not living her life for other people.

LiLo insists she's going for the music and wants to have some fun -- just like last year (above) -- before checking into the rehab facility for a 90-day stay.

Lindsay is also insisting she doesn't have a problem with drugs or alcohol ... leading lots of us to wonder how on earth rehab is going to work.  In fact, Michael Lohan told us Thursday on TMZ Live ... he expects his daughter will fail.

And there's this ... The judge in her criminal case warned her to stay away from people who do drugs or alcohol.  This is an IMPOSSIBILITY at Coachella.

The rebound is officially underway for Katy Perry ... who was all about the PDA with her new man at Coachella ... hugging, caressing and full on making out.

The guy is Robert Ackroyd -- the guitar player for Florence and The Machine.

The two were also spotted together at the music festival last weekend ... and according to some reports, Katy was already referring to him as her "boyfriend."

Guess she's finally ready to move on from her soon-to-be ex-husband Russell Brand -- who filed for divorce back in December.

As TMZ has previously reported, Brand and Perry have been on relatively good terms since the breakup ... with Brand refusing to make a play for any of the millions of dollars Perry raked in during their relationship.

Suge Knight is FURIOUS over the look of 2Pac's hologram at Coachella ... telling TMZ the people who created it screwed up one major detail.

The rapper was out in Los Angeles last night when he pointed out that the 3D hologram used to bring 2Pac to life on stage was missing the rapper's famous Death Row Records chain.

Knight told us, "At the end of the day, how you gonna take the Death Row chain off Pac? That's like taking the Raiders symbol off the Raiders."

Dr. Dre says he's THRILLED with the way his Tupac hologram rocked Coachella this weekend ... and tells TMZ he would love to see a Jimi Hendrix-ogram follow Pac's lead.

The hip-hop legend was at Boa steakhouse in Hollywood last night when he told us he's so fired up about the Tupac show, he's breaking out the hologram AGAIN at the next Coachella concert on Sunday ... and he's even thinking about taking Pac on tour.

Dre says he's hopeful the 2pac concert will inspire other artists to resurrect legendary musicians like Jimi Hendrix and Marvin Gaye.

Hell. Yes.

One member of the Lohan family caused serious problems at Coachella this weekend -- garnering noise and smoking complaints at a Palm Springs hotel -- but it wasn't the Lohan you'd expect ...

Sources tell TMZ, 24-year-old Michael Lohan Jr. was staying at the Hyatt Grand Champions Resort in Indian Wells, CA -- and around 3AM Friday morning, the hotel received a noise complaint about his room.

We're told hotel management paid a visit to Michael's room after the complaint -- and the party inside agreed to keep the volume down.

But it didn't end there -- we're told someone then made a complaint about someone smoking in Michael's room ... and hotel management was forced to pay the room ANOTHER visit.

We're told management informed the room's occupants it was non-smoking only -- and the smoker put out his cigarette.

We're told the hotel did not assess Michael a smoking fee.


MiLo Jr. tells TMZ, “I drove from LA to the desert at 1am and went to sleep within 20 minutes of arriving  ... Others went to another room where a noise complaint may have been filed. Never were we involved in a complaint nor do either of us smoke cigarettes."