'Out of the Blue' is a phrase that's used when someone or something appears from nowhere. It's also the title of the first album by 80s pop starlet Debbie Gibson and makes for an appropriate description. As a seventeen-year-old she went from a complete unknown to a huge star overnight. You could say she was the template for Britney Spears, although the latter has enjoyed more longevity at the top level.
Gibson was more than just a pretty face though; if anything, her looks hampered her ability to be taken seriously as a musician. While other performers needed other people to write and produce their songs for them, Gibson did it all herself. Not having to share the royalties with many people would have been a big plus for her when her second album 'Electric Youth' went double platinum.