It was a mellow, carefree Friday night for Zac Efron.

The Townies star kept a low profile at West Hollywood hotspot Bootsy Bellows, where he hung out with pals in the VIP room at a table in the way back corner of the club.

Clad all in black, with a beanie covering his head, the star sipped on vodka cocktails and danced to Drake's "Started from the Bottom."

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We're not in Hogwarts anymore.

Daniel Radcliffe made an unexpected appearance at Bootsy Bellows in West Hollywood on Friday night. Arriving with a male pal around 1:40 a.m., the Harry Potter star was "in party mode but really friendly," an onlooker tells PEOPLE.

Wearing a long-sleeved black shirt and jeans, the actor hung out at a table in the club's back VIP room, where he made himself vodka cocktails.

As DJ BeeFowl spun hit after hit, Radcliffe "started singing and dancing at the table to Nelly's 'Country Grammar' and 'Ride Wit Me'," the source adds. "He introduced himself to people at his table casually as 'Dan.' "

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Leonardo DiCaprio may have lost the Golden Globe for his role in Django Unchained, but that didn't stop the actor from enjoying himself a few nights later.

Alongside best friend Lukas Haas, DiCaprio visited West Hollywood hot spot Bootsy Bellows on Tuesday night.

Donning a newsboy hat, DiCaprio mingled with club promoters, while Haas did "his own thing," an onlooker tells PEOPLE. "Leo hung back and sat on top of the banquette. He was getting a ton of attention from the ladies."

The usually quiet DiCaprio was "upbeat" and "even danced and clapped along" as music from Jay-Z and Kanye West played. And when the actor was approached by other clubgoers, he was "very gracious and chatted with them for a few minutes," the source adds.

Once the lights came on, the two friends reconvened to figure out their plans for the rest of the night.

Oh, what a night!

New mom Nicole "Snooki" Polizzi enjoyed a night out without baby Lorenzo Tuesday, linking up with Jersey Shore costar Deena Cortese to toast the end of their show at West Hollywood hotspot Bootsy Bellows. But the ladies had some random company, in the form of Real Housewives of Beverly Hills star Kyle Richards and her friend, Faye Resnick.

The foursome – there with a few other pals – arrived around 11:50 p.m. and went to the club's VIP room before hitting the dance floor – hard. The group busted moves to songs like James Brown's "Get Up (I Feel Like Being a) Sex Machine" and Jackson 5's "I Want You Back" while sipping vodka cocktails (Richards abstained from alcohol).

Once Cortese spotted club owner David Arquette, she told him, "You need to take a picture with the two meatballs. You're the sausage!" So the actor obliged, posing for a shot with Cortese and Polizzi, later seeking them out to entertain them with his Keith Richards marionette.

Resnick and Richards left around 12:30 a.m., at which time Dancing with the Stars pro Derek Hough came over to the Jersey Shore stars to say hello – just as Cortese took a tumble backward and broke a few glasses at her table.

At 1 a.m., Cortese and Polizzi left the VIP room and headed for the main part of the club to enjoy some house music, and ran into Glee star Amber Riley, who joined them at a table for a bit.

Meanwhile, Julianne Hough arrived around 1:15 a.m. (sans boyfriend Ryan Seacrest) and immediately hit the dance floor, grooving to the Spice Girls's "Wannabe" and AC/DC's "Back in Black." But when the DJ spun Dion's classic "Runaround Sue," Derek joined Julianne on the dance floor and the two broke out into a full-on choreographed routine. The dance floor cleared as people cheered them on – especially when Derek fell into the splits (more than once!). Julianne left not long after, around 1:40 a.m., and Cortese and Polizzi slipped out a few minutes (and cocktails) later. – Jennifer Garcia

After celebrating at the GQ Men of the Year bash in Hollywood on Tuesday, Breaking Bad's Aaron Paul hit up hotspot Bootsy Bellows with a group of guy friends.

The actor and his pals arrived around 1:30 a.m. and hung out in the back VIP room, opting to party on the dance floor instead of at a table. Paul got "incredibly excited" when the DJ spun Michael Jackson's "Thiller," a source tells PEOPLE, and afterward, ran out of the VIP room, returning soon after with Pat Benatar's daughter, Haley Giraldo. The two seemed like old friends and danced to Marvin Gaye and Tammi Terrell's "Ain't No Mountain High Enough" before Paul, who sipped on vodka cocktails throughout the evening, rocked out to the Four Tops hit "It's the Same Old Song."

Though Paul was without his fiancée, Lauren Parsekian, he "seemed really jovial and excited to be out with his boys all night," the source says. The guys had so much fun that they stayed until the lights came on and the club was closing.
– Jennifer Garcia

The final season of Jersey Shore is quickly approaching, but that doesn't mean the party's over just yet!

Paul "Pauly D" DelVecchio, Mike "The Situation" Sorrentino and Ronnie Ortiz-Magro spent a night out at Bootsy Bellows in West Hollywood on Tuesday.

Wearing their signature T-shirts, the cast mates arrived around 11:30 p.m. but didn't spend too much time together.

Nestled in a VIP room, "Ronnie spent a lot of time texting and on his phone while Mike was laid back and relaxed," an onlooker tells PEOPLE. "Pauly was the most social chatting with a lot of people."

Around 12:15 p.m. Pauly left the VIP room to say hello to Paris Hilton.

While there was no fist-pumping to be seen, that didn't stop the Jersey Shore stars from staying until the club closed.
– Jennifer Garcia

Funny seeing you here!

Zac Efron and Cheryl Burke crossed paths when they both stepped out at Bootsy Bellows in West Hollywood on Tuesday.

Although they were spotted hanging together at the club just a few weeks ago, the stars had two very different nights.

Sporting a blue button-down shirt, a black beanie and a bit of facial hair, Efron kept a low profile in the club's back VIP room.

"His table was very crowded but he always seemed to be at the back of the crowd so he could have some privacy," an onlooker tells PEOPLE.

Even though Efron seemed focused on a laid-back night with his friends, a female patron managed to catch his eye.

"At one point, he was flirting with a tall, thin blonde. He was definitely charming her," the source adds. "But he left the club alone when they closed at 2 a.m."

While Efron kept his evening low-key, Burke made a fashionably late entrance, arriving around 1:20 a.m.

Wearing a white Grecian-inspired dress, the Dancing with the Stars pro was upbeat as she chatted with her friend, promoter Allison Melnick before hitting the dance floor.

"She wasn't shy and busted out her dance moves to songs like Rihanna's 'Birthday [Cake.]' She was having fun," says a source.