Usher, 36, is said to have popped the question with a dazzling diamond ring and 44-year-old Grace didn't hesitate in saying 'yes'.
The couple have been dating since 2009 and have worked together, with Grace acting has his manager, for around three years.
Speaking to Billboard in October, Usher said: "I have an incredible partner and manager.
"She has helped me through some of the hardest times in my life and my career."
Usher was previously married to Tameka Foster, his personal stylist, however their relationship came to an end in 2009.
The couple had tied-the-knot two year's earlier in Atlanta, Georgia, and Usher has since described the experience as his "best mistake".
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