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The weekend is here, which means its time to get your party on! But if you're planning on hitting some of these East Coast-West Coast playgrounds, you might want to have a back-up plan.

In Los Angeles, where the stars really do come out at night, the competition to get in the club-of-the-moment is brutal. Known as a home-away-from home for the likes of Lauren Conrad and Brody Jenner, the West Hollywood vintage lounge Crown Bar runs a tough rope (especially on a Wednesday night) where only the hottest and most well-connected peeps can slip through.

This is a lesson "American Idol" big-wig Nigel Lythgoe recently learned the hard way. Despite the fact that pal Ryan Seacrest booked him a pricey table to celebrate his birthday, Nigel was turned away at the front with every pap in town rolling on it. Others that have been caught on the wrong side of Crown Bar rope include Golden Brooks and Alli Simms.

Expect to see the likes of Leonardo DiCaprio, Paris Hilton and Lindsay Lohan lurking beneath the low-ceilings and red hues of the very dark New York-like Apple Lounge. The place prides itself on being star-studded, so even swarms of gorgeous-looking girls get turned down.

Situated inside popular eatery STK, super small lounge Coco De Ville accommodates a varied crowd from "The Hills" hotties (Frankie Delgado promotes Tuesday nights) to Kim Kardashian, Tila Tequila and the A-list likes of Jamie Foxx and Diddy. Hollywood's top agents and attornies also frequent this swanky spot, which is so exclusive there is no way yo ucan get on the list, because there isn't one.

Teddy's, a lounge housed in Hollywood's historic Roosevelt Hotel, is known for its tight door and upscale crowd of celebs and the industry elite. Once inside, guests are greeted with a cavernous and sexy environment complete with dim lighting and leather bars and the best music selection around. Celebrities can mingle amid the partiers or slip away in one of the club's private corners.

Despite the club's size, Teddy's door is known for turning away celebs with entourages. John Legend was denied after winning a Grammy because of his post-win posse of 15.

Uber-upscale Villa looks like a billionaire's livingroom. Treated as a highly exclusive and lavishly sexy house party, the only way to gain access is to have a relationship with someone in the Villa family. Thus the door remains one of the tightest in Hollywood. Being a celebrity does not ensure your entrance; even Britney Spears was denied by the iron door. Former pimp Jason Itzler was also denied access to the L.A. lounge, as was Donald Trump's "Celebrity Apprentice" Omarosa Manigault-Stallworth.

And even if your parents are Hollywood powerhouses Demi Moore and Bruce Willis, if you are underage, Villa is a no-go zone. A lesson young Rumer Willis learned the hard way.

Click here to see Rumer be denied.

But the toughest Hollywood club of all is still Hyde, which can only hold about 100 people and is described by a L.A. nightclub insider as "the size of my college dorm suite." Hyde has become a staple of the city's nightlife scene akin to the city's heralded eateries Spagos and Mr. Chow. "This place remains a fortress," our insider said.

In NewYork, the nightlife isn't nearly as cutthroat as Lalaland, but party-seekers still need more than beautiful smiles and overstuffed wallets to get in. Celebrities rule these roosts, so not-so-famous night owls can only be so lucky to score a place in line on the sidewalk.

At the West Village's Beatrice Inn, celebs from LiLo to Mary-Kate Olsen pack into the tiny hipster lounge with a who's who of Manhattan's club kids. Conveniently located only a few blocks from elite eatery, the Waverly Inn, Beatrice Inn offers Hollywood 's young A-list crowd the perfect location to congregate and dance off those extra dinner calories.

Dubbed "the next Bungalow 8" by the former hotspot's owner, Amy Sacco, is the newly opened Eldridge on the city's trendy Lower East Side. The front of the tiny establishment looks like a bookstore with a display of paperbacks and hard covers, but inside at any of the 16 small tables, there's not much reading going on. With a place that intimate, only a select few are invited in, among those Taryn Manning and Kirsten Dunst.

Nightlife impresarios Richie Akiva and Scott Sartiano, who are responsible for the success of celeb haunt Butter (and several failed relationships with some of Tinseltown's leading ladies) keep their door at their West side joint, 1Oak, just as tight. Frequented by Adam Levine, Heidi Montag and Spencer Pratt, 1Oak features plenty of space and music by well-known DJ Cassidy, who spun tunes at Beyonce and Jay-Z's nuptials and who keeps the party going all night long.

Foxnews.com's Hollie McKay contributed to this report.