CHICAGO, IL - This weekend was FULL of surprises in Chicago as Jennifer Lopez rock the stage at the B96 Radio Pepsi Summerbash at Toyota Park.

Jennifer Lopez joined an line-up of Jason Derulo, Austin Mahone, Pitbull, Iggy Azalea, Little Mix, Icona Pop, Hot Chelle Rae & G.R.L.

Lopez gave Chicago a couple surprises as she came to promote her forthcoming album, 'A.K.A.' as it is out TODAY!

First Lopez, gave Chicago a taste showing them that she's got an BIG booty, by debuting the song which features Pitbull on her new album. Then Lopez hit Chicago with debuting 'Acting Like That' by bringing out the feature artist, Iggy Azalea, to the stage to help her.

You can purchase 'A.K.A' which is available now HERE via Itunes.

Watch JLo give Chicago a taste of her BIG booty below.