Adam Levine Has a Guys' Night – with Matthew Morrison & Cash Warren – to Celebrate His Details Cover
05/31/2012 AT 06:00 AM EDT
Pulling up in his Aston Martin, Levine and a couple guy pals met up inside with Glee's Matthew Morrison and Jessica Alba's hubby Cash Warren.
"The trio sat at the bar all smiles, sipping beer and catching up," an onlooker tells PEOPLE.
Also coming out to support the Maroon 5 frontman – who was dressed down in jeans, sneakers, a T-shirt and sporty jacket – was Seth Rogen's wife Lauren Miller, who the source says "looked stunning in a great cocktail dress."
– Jennifer Garcia