If classical composers were provided electric guitars, basses, keyboards and drum sets; they'd probably make music that sounds similar to Yes. The English group was founded in the late 60s and is primarily known for combining elements of symphonic orchestrations with aspects of progressive rock. The band's songs tend to highlight each members instrumental prowess and though the group has transcended multiple music genres, it is best regarded for its innovation with the progressive rock genre.
It's kind of surprising that more pop stars don't trace their entertainment stardom to the stage, more specifically - Broadway plays. The productions are a breeding ground for talented individuals who can sing, as well as dance, and it seems like only a marginal amount of mainstream singers emerge from the stage. One vocalist who did, though, is English-born Sarah Brightman. Though she doesn't write her own songs, she looks good and can sing fairly well. She rose to stardom as a dancer and singer but then migrated to the world of pop music in the 1990s.