This is what they look like.
This is the new dark blue with mint green baby sing a ma jig duet. This is a birthday Sing-a-ma-jig Duet. The big one is dark blue with sky blue hair, the same ears as the big one from the plum sing a ma jig duet, pentagon eyes, a green nose and a magenta mouth. It has the same hands as the birthday sing a ma jig and the same feet as the lemon. The little one is mint green with round eyes, a light blue nose, a black mouth, trapezoid ears, the same hands as the koala from the silver duet, and the same feet as the new yellow. They sing "Happy Birthday! To You" as well. The big one has the same voice as the orange one and the little one has the same voice as the midnight blue one.
Sign in: Both of them: "Happy Birthday!"
Song mode: Big one: "It's Birthday Time!" Little one: "Sing Along!"
Sign off: Big one: "Bye Bye Birthday!" Little one: "Can we have cake too?"