Rihanna & Drake romance heats up: rapper sends Chris Brown's ex sexy 'happy birthday' shout-out, RiRi responds with much love! Couple dating or hooking up?

Rihanna celebrated her 26th birthday on Thursday (February 20). The "Diamonds" songstress shacked-up in the snowy mountains with a group of girlfriends to enjoy the b-day festivities. But what about rumored boyfriend, Drizzy Drake? Apparently, the Nothing Was the Same rapper sent RiRi a sweet "happy birthday" message, and the Barbadian beauty happily responded with "much love!" Are the two officially dating?

RIRI NEWS: Eminem & Rihanna tour! 'The Monster' duo announce stadium concerts in New York, LA, Detroit for August 2014! [DETAILS]

An alleged insider reveals to Hollywood Life, "Drake gave her a shout-out. He hit her up, asked how she's doing and how she feels on her 26th.

And Rihanna's response?

"She said, 'I'm good, Pa, thank you and much love to you.' He didn't want to keep her too long because he knows she's enjoying herself with friends."

Looks like they have a pretty understanding relationship!

Rumors suggest that Drizzy and Chris Brown's ex enjoy partying and "hooking up," but they're not exclusive (although the Young Money star DID send RiRi and her mom an adorable Valentine's Day surprise).

Do Mstars fans think they'd make a cute couple?