Clarkson also wished that her baby will sleep through the night, reported Contactmusic.
"It's my birthday! For my birthday I have asked my unborn baby girl to sleep through the night and laugh a lot when she comes out (sic)," Clarkson tweeted.
The 'Stronger' hitmaker is expecting her first child with husband Brandon Blackstock and made a wish on her birthday On April 24 that her baby will make motherhood easy for her.
The 'Breakaway' singer married Brandon, who has two children from his first marriage, Seth, seven, and Savannah, 11, in a low-key ceremony in Tennessee last October.