The actor, 55, plans to wed girlfriend, Kayte Walsh, 29, at the end of February in New York, a source confirms to PEOPLE.
The wedding plans are already in motion and "it's going to be beautiful," according to the source.
Grammer is not yet divorced from Real Housewives of Beverly Hills star Camille Grammer, 42. However, the couple have a hearing set for Feb. 7 at which Judge Maren E. Nelson will consider granting Kelsey's request to be declared legally single again.
The Frasier star has been keeping mum on wedding details, but has said he's eager for a private ceremony surrounded by friends.
"Kayte and I are marrying because we are engaged, and we are engaged because we are in love and see no reason to postpone our happiness any longer," he told PEOPLE in December.