Kanye West acknowledged his engagement to Kim Kardashian for the first time publicly at a concert in California on Tuesday (22Oct13) by dedicating a song to his "fiancee". The Jesus Walks hitmaker popped the question to the reality star with a 15-carat Lorraine Schwartz bauble on her 33rd birthday on Monday (21Oct13), after taking over the San Francisco Giants' baseball stadium for the grand gesture. And, while performing in nearby San Jose, California on Tuesday (22Oct13), the rapper dedicated Bound 2, a song he wrote about his relationship with Kardashian, to the mother of his daughter. He told the crowd, "You know what song this is, right? I want to sing this song to the birthday girl that's back there right now, my fiancee. "If you came with somebody that you love tonight, hold on so tight."