Brad Paisley literally took the hat off his head to give to a fan at the H20 World Tour close this weekend in Tulsa. Sierra Kihega was holding a poster in honor of her friend, which read "Cancer Sucks ... 13-year-old Kenya [Potthier] wanted to be here. Could you sign something for her?" Brad took off his signature Stetson, which has a tag that reads "Especially made for Brad Paisley," and handed it to Sierra. Brad even went a step further after the show, signing the hat, as well as an additional one for Sierra. Watch an interview with the girls on WSMV-TV/Nashville here.