Carrie Underwood says her newborn son is the best birthday gift ever.

The 'Blown Away' hitmaker, who gave birth to Isaiah Michael Fisher 11 days ago with husband Mike Fisher, was thrilled to kick off her 32nd birthday celebrations with ''a tiny semi-bald chubby dude'' in the early hours of this morning (10.03.15).

The blonde beauty wrote on Twitter: ''HAPPY BIRTHDAY TO ME! My 1st present = late night date with a tiny semi-bald chubby dude who likes to grunt & cry & pass gas! #bestgiftever''

Carrie introduced her first child to her Facebook followers last week, writing: ''Tiny hands and tiny feet ... God has blessed us with an amazing gift! Isaiah Michael Fisher -- born February 27.''

She also posted a photograph of the tot snuggled up in grey and white clothing, but concealed his face.

The former 'American Idol' star's husband, who is a professional ice hockey player, later thanked their fans for their support, writing: ''Thanks for all the prayers and wishes over the past week! Having a child is the best thing in the world!''

Shortly before giving birth, Carrie admitted she was looking forward to getting her body back.

She said: ''I'm looking forward to reclaiming my body. I've been saying it's been on loan for the past many months ... I'm excited to take it back.''

But she insisted she loved being pregnant.

She said: ''The whole process itself [has been] really beautiful. Even when I feel pretty large, it really is such a miracle and such a beautiful thing.''