On the heels of Britney Spears' broken engagement comes sister Jamie Lynn's engagement, reports People. The 21-year-old posted a photo of herself, her new fiance Jamie Watson, and her new rock to Instagram last night, captioned, "Guesssss what?????? #Hedidgood." The couple have been dating for three years, 30-year-old Watson said in an interview last month. Spears is mom to Maddie, 4; she had previously been engaged to babydaddy Casey Aldridge.