Rihanna headed out for a tattoo and to celebrate Chris Brown's birthday

They've both denied rumors that they're dating, but last night Chris Brown and Rihanna didn't do much to stop the rumor mill from churning.

The "Kiss Kiss" stud and his "Umbrella" babe were spotted out and about in New York City, making a few stops together before heading back to the same hotel.

First, Rihanna gratified her desire for ink, stopping into WHATEVER Tattoo parlor for a nice neck/back tat. Of course, fans and paps made the whole ordeal more complicated, with bodyguards, as well as the NYPD getting involved.

Then the "just friends" couple headed over to the Hotel Chelsea for Rihanna's friend's birthday party. And the "Good Girl Gone Bad" was dressed to impress.

She sported a classic little black leather dress and black stockings, along with matching black heels and, at times, a green hooded pullover. And Chris looked the R&B singer part, sporting a baggy grey screen-printed shirt with baggy jeans and sneakers.

Enjoy the pictures of Rihanna and Chris out for the birthday celebrations (April 8).