Britney Spears Grabs Drinks With Friends at L.A. Restaurant

Britney Spears brought the "Circus" to an L.A. eatery Wednesday night ... exciting patrons of the place when she walked in for food and drinks with her friends.

The singer-songwriter hit up RED O in Thousand Oaks -- a suburb of L.A. about 15 miles from the city -- standing out in a bright yellow blouse which bared her shoulders, and a fashionable black hat.

Eyewitnesses tell TMZ Britney was in good spirits ... complimenting others on their outfits and even taking pics at the bar with a few of her fans.

We're told Britney and her crew hung out for about an hour ... ordering food and a round of drinks. We're told this is the first time Britney's been to this spot -- but, we'd guess they'd love to have her back.

After enjoying themselves for a bit, Brit was spotted leaving with an assistant holding her hand ... before she hopped in her car and drove herself home.

Spears took the opportunity to blow off some steam after a couple weeks of dealing with rumors and the media furor over her ex Kevin Federline's new memoir "You Thought You Knew" ... in which he made a series of inflammatory claims.

K-Fed accused Britney of using cocaine while she was still breastfeeding her kids, cheating on him with a female dancer on her tour, and calling Justin Timberlake the night before Federline and Spears married.

Spears has denied the book claims in a series of angry social media posts ... and, she says K-Fed only wrote it to make money 'cause she hasn't paid him a single cent in five years -- adding, "If you really love someone then you don’t help them by humiliating them."