Miley Cyrus is engaged to musician Maxx Morando after four years of dating.The couple let the news slip at the world premiere of Avatar: Fire and Ash in Los Angeles, CA on Monday (December 1), where Miley was seen not hiding an impressive diamond ring on her left ring finger. Miley posted photos from the night, quoting "Dream As One," her original song from the film: "Baby, when we dream we dream as one."