Long and Barrymore party with a pal in Las Vegas
Courtesy Pure Management Group
01/17/2008 AT 02:25 PM EST
Having spent Thanksgiving with his family
, Justin Long and Drew Barrymore
kept it all in the family Wednesday night in Las Vegas.
The couple, who were first spotted together
last summer, hit the Pussycat Dolls Lounge in celebration of Long's brother Christain's 26th birthday.
"They were very affectionate," an onlooker tells PEOPLE of the celeb couple.
After catching the 11:30 p.m. show and toasting the birthday boy with champagne, Barrymore, 32, and Long, 29, headed to Noir Bar– where they sat at a VIP table and downed Grey Goose vodka and soda.
"They looked adorable," a source tells PEOPLE.
Also at Noir was singerChris Daughtry and his band.
– David Caplan, Jennifer Garcia and Mark Gray