The Voice UK coach spoke out on social networking site Twitter earlier today, after coming across negative comments about her body posted online.
The 25-year-old declared that she was "proud" of her body and told fans to "embrace" themselves.
In a lengthy message, she told her legion of Twitter followers: "So I'm seeing this weird debate on my pictures and people saying "you have small boobs" yes I do and I have very long legs and a small waist and small shoulders and size 6 feet! And I am proud of what I have!
"All girls should embrace what makes them unique. Stop being so negative about each other! Be proud! Boobs or no boobs!"
This is not the first time that the outspoken 'Domino' singer has taken to Twitter to air her thoughts. In March, Jessie blasted online bullies again for judging her personal life.
Jessie, who recently flaunted her body in just her underwear for new music video 'Wild', also reassured a fan who said: "I have small boobs and I see it as a massive insecurity :( but true words Jessie." Jessie simply replied, "Don't! Be proud!"
Watch Jessie J's new single 'Wild' with Dizzee Rascal and Big Sean below.