Rihanna Stays Out In Hollywood Until 2:45am

She certainly is a night owl!

Rihanna went to dinner at Scarpetta restaurant at the Montage Hotel last night, and after that she partied at Colony until 2:45am. RiRi flew in from NYC the previous night, so it looks like she's still on east coast time!

While the 24-year-old R&B starlet was having a blast with her girlfriends last night, her ex-boyfriend Chris Brown's new ladylove Karrueche Tran was busy posting cryptic tweets. Karrueche wrote, “Don’t become your worst enemy," and over the weekend she retweeted Notebook of Love, writing, “Just because someone puts you down doesn’t mean what they say is true, it only proves that you’re better than them and their negativity.” Um, bitter much?

Rihanna has yet to respond, but we're guessing she's over it -- after all, she's got much bigger fish to fry!