Katy Perry: Bootsy Bellows with Justin Bieber & Selena Gomez!

Katy Perry arrives at the Bootsy Bellows lounge with pals Justin Bieber, Selena Gomez, and Robert Pattinson in West Hollywood on Tuesday (June 26).

The foursome headed to a private room in the back of the lounge, which is owned by David Arquette, Brian Toll, Darren Dzienciol, and John Terzian.

Emma Roberts, who spotted at the lounge with pal Christy Cham, partied separately from her exes Chord Overstreet and Alex Pettyfer. Zelda Williams was also in the house!

Earlier in the evening was the official premiere after-party for the concert movie Katy Perry: Part of Me 3D, which was held at the exclusive Chateau Marmont.

“Justin and Selena shared a table with friends,” a spywitness tells JustJared.com of the after-party. “They were very affectionate the whole night, holding hands and sharing kisses. Katy and Amber Heard, and Shannon Woodward spent a good portion of the night sitting and chatting with them. Everyone was laughing and having a great time, taking pictures with each other and snacking on mini-cupcakes.”

Ashley Benson (in Ash boots) and Chord left the after-party together, which was also attended by Queen Latifah and Carly Rae Jepsen.

Bootsy Bellows is a lounge filled with burlesque and life-size dancing puppets and old-school Las Vegas show ballroom decor. The place is named after David Arquette‘s mom, who was a burlesque dancer!

FYI: Katy paired her Vivienne Westwood dress with Christian Louboutin shoes.

50+ pictures inside of Katy Perry and crew at Bootsy Bellows…