Watch Katharine McPhee and James Corden Joyfully Sing Tax Day Carols

"My grandpa left to me ... one crummy lump sum."

James Corden is on a musical streak on The Late Late Show, and his latest endeavor was perfectly timed to coincide with a special fiscal day. Corden and guest Katharine McPhee got decked out in their best accountant gear to sing "Tax Day carols" on April 15.

The duo's "holiday" cheer was infectious as they sang carols rewritten with lyrics like "My grandpa left to me ... one crummy lump sum" and the story of the "little trust-fund boy." Who needs Santa Claus when you have Uncle Sam sneaking in your window with an empty sack to take your possessions?