Pom Klementieff in a 2012 short that I have never heard of (El Turrff). (Samples below) Pom plays Mantis in the Avengers/Guardians movies.
I reckon nobody else has heard of this film either, since it has a whopping five votes at IMDb. The entire film is available on Vimeo. (Thanks to Oz for finding it.) The nudity starts at 6:02
Here is Pom in another topless scene in Hacker’s Game (2015)
That is exactly what I expected her breasts to look like. I’m delighted.