Since Kate Middleton was made Colonel of the Irish Guards, this was their first St. Patrick's Day celebration together.

Kate wore a teal ensemble to coordinate with the feathers in the Irish Guards' caps.

The color of her outfit is actually called St. Patrick's blue.

Kate wore a Catherine Walker & Co coat dress with a matching fascinator and heels in the St. Patrick's blue hue.

She accessorized with a gold shamrock pin and stud earrings with teal stones.

William gave a speech saying it was his 13th and final St. Patrick's Day as Colonel and he was proud of the title.

Kate spoke about being proud to be their Colonel and looking forward to supporting and championing them.

William was Colonel of the Welsh Guards before becoming Prince of Wales.

Kate's responsibility as Colonel is to listen, support, and champion the Irish Guards.