It's beginning to seem like Britney Spears has a sip from the Fountain of Youth for breakfast every day, because the "Pretty Girls" singer looks more radiant than ever in yet another steamy Instagram video. In the clip, which she uploaded on Tuesday morning, an incredibly fit Britney shows off some black lingerie, a set of toned abs, and two massive tattoos while she dances to an upbeat version of her song "Breathe on Me." Along with the video, she wrote, "Girls just wanna have fun 😉 Never released a video for this song . . . so decided to do a little tease on Instagram instead . . . enjoy!!" Check out her moves above, then see what happened when she met Hillary Clinton!