“Getting ready for my performance … also pumping. Multitasking,” “#ACMAwards,” “#Southbound” and “#LetsDoThis,” Underwood captioned the post.
Underwood, 36, gave birth to her second child, Jacob Bryan, with husband Mike Fisher in January. They also share son Isaiah Michael.
On Sunday, Underwood joined “This Is Us” actress Chrissy Metz on stage to perform “I’m Standing With You." She also sang "Southbound" off her most recent album "Cry Pretty."
The awards show marked Underwood's first red carpet appearance since welcoming her second child. Underwood dazzled in a shimmering over-the-shoulder black and gray sequin dress complete with two thigh slits that left both of her toned legs exposed.
Underwood looked confident despite sharing in an Instagram post last month that she was having a difficult time “bouncing back” to her pre-pregnancy body since giving birth to Jacob just two months ago.
“I’m going to be honest, 'bouncing back' after having Jacob has been much more difficult than after I had Isaiah and I’ve been pretty hard on myself lately. I go into the gym and I can’t run as fast or as far,” Underwood wrote in a lengthy post.
Fox News' Julius Young contributed to this report.