The interface between popular and classical music always holds the promise of innovation -- a promise not often realized. Brahms wrote waltzes, the popular dance form of the day. Leroy Anderson created short orchestral bonbons that spoke the vernacular of tin pan alley. Gershwin easily moved between the opera house and Broadway, and so on.
A group of music students in Australia bring their classical training (and chops) to the world of pop. And the result (I think) might possibly be considered alt-classical. While covering current Top 40 hits, Aston doesn't simply play a note-for-note recreation. Rather, the original song is merely the starting point.
Aston features an unusual line up that's more in line with a contemporary chamber ensemble rather than a pop group. And that results in a neo-classical sound that's not out of line with contemporary classical music.
So give it a listen. The less familiar you are with the original, the more "classical" this may sound. Alt-classical, indeed.
Here's the original of Lady Gaga's "Telephone" for comparison.