Plus, more star sightings!
Credit: Jeff Kravitz/FilmMagic; Lucas Jackson/Reuters/Landov

The more, the merrier!

Steven Tyler and Vince Vaughn stepped out separately at Sunset Marquis’s Bar 1200 in West Hollywood on Monday night.

Both stars arrived around 10 p.m. – and didn’t seem to see each another, an onlooker tells PEOPLE.

“Steven was there with a group of guys and girls,” the source adds. “There was a birthday going on. He was posing with his friends for photos. They were laughing and having a great time.”

Meanwhile, Vaughn kept a low profile with a few male friends.

“They seemed like just ordinary guys going out to catch up together and share a few laughs,” the source says.

Wearing baggy jeans and running shoes, Vaughn was “super chatty and polite” to whomever walked by.
– Dahvi Shira