Miley Cyrus pokes funs at a viral 'Hannah Montana' moment to promote her new single, 'Used to Be Young.' The 30-year-old singer laughs about the 'goodbye' scene on the Disney Channel comedy's third season finale, which has become the subject of countless memes years later. Last week, fellow Disney starlet Selena Gomez posted some photos of herself with Miley on ‘Hannah Montana,’ in honor of both singers dropping new singles on Aug. 25.