R&B singer Christina Milian has reportedly joined Lil' Wayne's Young Money label, the home of Nicki Minaj and Drake, among others.  Milian posted the news on her Twitter page, just hours before Lil' Wayne introduced her as his label's latest addition at a pre-Grammy party.  The label will be home to Milian's oft-delayed fourth album, which has been in progress since 2008.  The day after news of Milian's new home hit a single, "Mr. Valentine," leaked on the Internet.  Neither a Young Money spokesman nor Milian have confirmed the track will be on the album.  Listen to "Mr. Valentine" below.