Ariana Grande Sued Over 'One Last Time' Rip-off

If the hook in Ariana Grande's hit song, "One Last Time," sounds familiar that's because she jacked it from a song that came out 2 years earlier ... according to a new lawsuit.

Songwriter Alex Greggs says he wrote, and holds the copyright on the 2012 tune, "Takes All Night" ... an EDM track for Skye Stevens.