And it involves Glee!!!
Watch (above) to get the scoop and then help us share the exciting news!!!!
Sienna Miller is a WHOLE new woman.
The adorbz new parents were seen getting some fresh air in NYC sans baby along with Sienna's doting mother Jo.
While we DO miss fashionista Sienna, we can just tell that she is GLOWING with happiness … even with that grumpy look on her face!
Oh, how the paparazzi just bring out the worst in people!
We just can't get over how good motherhood looks on you! And you shouldn't either!
[Image via Ramey Pix.]