One day after Carrie Underwood announced she was pregnant, congratulations have begun pouring in from country music's biggest stars. Miranda Lambert sent her friend and 'Somethin' Bad' costar a public note, posting to social media.

"Big congrats to my friend @carrieunderwood (aka Louise) on her big news!!!!" Lambert writes on Twitter and Facebook. "So happy for her and Mike!"

Underwood and Mike Fisher will welcome their first baby in Spring 2015. They made the official announcement on Labor Day (pun intended), and since then, they've been glowing in the millions of fans offering them words of support or advice. Scotty McCreery retweeted the songstress with a word of congrats to her and her husband. Brad Paisley gave his well-wishes, as well ... and it's almost certain the topic will come up when he and Underwood host the CMA Awards together in November.

You Think You Know Miranda Lambert?