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. In the suit, Greggs says Ariana and David Guetta -- who produced "One Last Time" -- duplicated the most memorable part of his song ... the chorus!

Greggs is a heavy hitter, who's worked with Lady Gaga, Justin Timberlake and both Jacksons -- Janet and Michael -- and says Ariana copied his music as well as lyrics, like ... "take(s) [or taking] you home."

He's suing for a cut of the profits from AG's track, a top 20 hit in 2014.

Go ahead and play juror ... check out both tunes.