LeAnn Rimes flaunted a noticeably bustier figure last week when she was on vacation in Mexico... and it’s because she recently got a boob job.

A source says the singer/actress was always insecure about her breast size--  a small A-cup. So, she got implants.

And the source says LeAnn used the same plastic surgeon that fiancé Eddie Cibrian’s ex-wife Brandi Glanville used... and got the same cup size as her. 

That is weird that leann got the same size breasts as her fiance's ex and she constantly Tweets about ther...what the heck is going on w Leann..Do think being in the spotlight SO YOUNG has made her a little...'off'?

Charli