The singer-and-actress - who is engaged to former NFL player Eric Johnson - is reportedly unhappy with her large boobs and believes downsizing her assets before tying the knot will help her to look better in her wedding dress.
A source told In Touch Weekly magazine: "She thinks if she downsizes her breasts, she will look smaller. She`s never loved having a huge chest."
Jessica, 31, has previously admitted she struggled to cope with her massive bust when she was younger and admitted she considered strapping down her breasts to make them look smaller.
She said: "I was well-endowed when I was in sixth grade. There`s no way to hide them, as much as you want to bandage your boobs down.
"I was the first girl in my class to wear a bra. I remember crying in the bathtub. All my friends were super-skinny."
Jessica - who was previously married to Nick Lachey - is also determined to get in shape for her nuptials by following her own exercise regime.
She said: "I am going to dance around my bedroom and hopefully lose some weight - and lift some weights and do what I can!
"I just have to work out on my own. There is no regimen I need to follow. There`s no diet I need to follow. I just need to do some things for myself and that`s it. And that will make me feel the happiest."