Rihanna jealous of Nicki Minaj's large boobs?

Rihanna is a beautiful girl but could she be more if her boobs were bigger?

At the launch of Jay Z's $56 million-worth Tidal music streaming service on March 30, bad girl RiRi was caught stirring at Nicki Minaj's famous big boobs 'jealously'.

Both singers were standing next to each other after been called up on stage to publicly sign their declarations as part owners of the new company.

Rihanna went bra less in a Christian Dior Spring collection pinkish suit exposing her well-known chest tattoo; while Nicki wore an little black sheer dress covered in a pink coat... but it wasn't big enough to cover her revealing cleavage.

RiRi was caught looking through Nicki's sheer black dress to perhaps measure up her size of her breasts..