Reba McEntire kicked off 2014 with her secret to staying fit and healthy -- juicing -- and now she's showing the world how her digestive system stays balanced. The country icon is featured in a 2014 Activia commercial, Activia Tummies. Happy People.

The thirty-second ad spot features McEntire, world-class professional boxer Laila Ali and renowned health expert and star of 'The Doctors,' Dr. Travis Stork -- the brand's spokespeople (called Activiaists).

McEntire kicks off the speaking portion of the spot, saying in her distinctive drawl, "The secret to a great day? Start it with a big smile."

"That's why I start every day with Activia -- to help keep my digestive system in balance," she continues. Interspersed throughout the Activia commercial are shots of the celebrities holding up photos of stomachs that line up perfectly with their own with smiley faces drawn on them, giving a visual to starting your day with a smiling tummy.

"When your tummy is smiling, you won't miss a beat," McEntire concludes.

The Activia Tummies. Happy People campaign will come to life in several thirty-second spots featuring the three Activiaists and their smiling tummies, and will be airing on a variety of early morning, daytime cable and primetime shows. In addition, to promote a healthy lifestyle, the campaign includes high-impact print insertions within influential women's health and lifestyle publications.

Go Reba!