Singer Usher is engaged to his long-time girlfriend and business partner Grace Miguel, sources have confirmed.

The couple have been together since 2009, following Usher's split from his ex-wife Tameka Foster.

`She's happy but they're trying to keep it quiet,` a source was quoted by usmagazine.com as saying.

Miguel's ring finger was noticeably adorned by a giant diamond ring at an event held Jan 10.