Congratulations need to be double

Happy birthday! Happy birthday!
Congratulations need to be double
On your very special day,
Otherwise there would be trouble.

You will always have each other,
To support, to listen, to love,
This relationship is like no other,
You both will ever have.

You look so much alike,
But act in different ways.
We never see you apart,
Not for a second, not for a day.

May your birthday be double the fun!