When Kanye West dropped “Only One,” an emotional track featuring keyboard improvisation by The Beatles’ Paul McCartney, we knew this was just the beginning. In fact, a press release at the time stated, “[The track] will be the first publicly available recording from what has become a prolific musical collaboration between these two legendary artists.” In a surprise move, however, the next West/McCartney collab comes out of Rihanna’s camp, not West’s. Today the Barbadian singer released a fresh song called “FourFiveSeconds” and interestingly none of the three artists are labeled as being featured guests. iTunes merely reads “Rihanna and Kanye West and Paul McCartney.” Whether the song lands on RiRi’s followup to Unapologetic or gets tagged with “Only One” on West upcoming seventh studio album is anybody’s guess. For now, preview and download the track at iTunes. It’s soft and acoustic, with Rihanna adding a bit of a country flair with her vocals. She harmonizes with West, who again leaves rapping behind here and sings with auto-tune assistance. McCartney strums a cool guitar all the while.