Fifteen years ago today, Hannah Montana premiered on the Disney Channel, turning Miley Cyrus (who was 11 years old when the show first started) into one of the most famous celebrities in the world. In 2011, the series came to an end after four seasons. In the finale, Miley Stewart reveals to her best friend Lilly that she'll be skipping out on college in order to pursue an acting job. She surprises her BFF when Lilly walks into her college dorm and realizes her roommate is Miley.It was a really sweet ending to a formative Disney Channel show. But after all these years, do we know why it ended? The quick answer to that is that Miley Cyrus felt like she had outgrown the role.Why did 'Hannah Montana' end?Hannah Montana came to an end after Miley Cyrus felt like she needed to move on. She was 18, and the the role just didn't feel right for her anymore. "I did [want to move on] once I was 18 because it felt ridiculous. The minute I had sex, I was kind of like, I can’t put the f***ing wig on again. It got weird. It just felt like … I was grown up," Miley told ELLE in 2019.That doesn't mean Hannah Montana won't ever get the reboot treatment. In 2020, Miley told Nashville's 107.5 The River radio station, "At some point, I’m definitely, I’m getting the wig out of storage,” when asked if she's interested in ever reprising the role of Hannah Montana. In fact, in a somewhat surprising and uncharacteristic move, Miley penned a long, sweet letter to her alter ego and posted it to Instagram today, March 24.She wrote, “Hi Hannah, it’s been a while. 15 years to be exact. Since the first time I slid those blonde bangs over my forehead in the best attempt to conceal my identity, then slipped into a puke-pink terrycloth robe with a bedazzled ‘HM’ over the [heart]. I didn’t know then … that is where you would live forever," and shared details like getting her period for the first time on set (while wearing white capris) and falling in love.Miley also sent around bouquets to all the people she'd worked with over the years, including Joe Jonas (The Jonas Brothers made an appearance on the series in 2007) and his wife, actress Sophie Turner (who was also a big fan). "Holy Hannah Montana! Thank you @mileycyrus, we love it! This is epic!" Joe wrote, and Sophie reposted, writing, "Thank u, Hannah we [love] u."Miley had given Joe and Sophie a note that read, "To Joe & Sophie! It was so sweet of you to name your daughter after me! Sending all my love to little miss Hannah Montana! Love, Hannah Montana." (The couple didn't actually name their daughter Hannah Montana — their daughter is actually named Willa.)These days, Miley is mostly focused on her singing career. She released her newest album, "Plastic Hearts," in 2020, sharing a clip from her new music video for "Angels Like You" on Instagram on March 12.We'll keep our fingers crossed there really is a Hannah Montana reboot someday soon.