This one's totally worth a peek. Carrie Underwood and her world-famous legs just stunned Instagram, with a photo of the 37-year-old singer landing on her CALIA by Carrie athleisurewear line's feed this weekend. The "Southbound" singer, now running a fitness empire, was proving the world's best brand ambassador for her 2015-founded company, with a snazzy, faux-leather leggings wardrobe doing wonders for the blonde insanely-scultped legs. In fact, the pants that were so tight, they appeared painted-on, even come with a sculpting benefit. Check it out below.