According to MissInfo.tv, the collaboration is indeed happening! Sources tell Info that Chris Brown laced the track and will be seen in the music video. Breezy reportedly sings and rhymes on the track, but we'll have to wait till next week, release date, to hear if both parts will be included.
Over the weekend, Chris Brown and Rihanna were seen leaving a West Hollywood studio, separately. Co-producers of "Birthday Cake," Da Internz -- comprised of Kosine and Tuo -- hinted on the collaboration when they told MTV News that the cameo on the track would "shock the world."