Little Mix, Austin Mahone & Jason Derulo Sizzle Up B96 Pepsi Summerbash in Chicago

Austin Mahone and Jason Derulo light up the stage during the 2014 B96 Pepsi Summerbash held at Toyota Park in Chicago, Ill., on Saturday afternoon (June 14).

The musicians were joined by Little Mix, who were also celebrating Jesy Nelson‘s 23rd birthday.

PHOTOS: Check out the latest pics of Little Mix

“Happy birthday to our beautiful Jesy! We love you so much! Talented, kind-hearted and beautiful! Have the best day! Turnnnn up!!!! L,J n Px,” the girls tweeted to Jesy.

Jade added more, “Didn’t get chance to say properly yday,happy bday to my beautiful sexy talented lovely jubbly sister hope it was the best day ever!”

15+ pics inside…