Pizzeria Vetri and Shake Shack are mashing menu items from Sept 1 to Sept. 10 at their locations in Philadelphia and Washington, D.C.

Shake Shack is lending its SmokeShack burger to Pizzeria Vetri, which will serve the SmokeShack Rotolo ($7). This collab is a twist on Pizzeria Vetri's rotolo. Usually pizza dough enveloping mortadella, ricotta, and pistachio pesto, the Shake Shack version will include ground beef, Niman Ranch bacon, Shack cheese sauce, and chopped cherry pepper.  It will be served at the Pizzeria Vetri locations in the Art Museum area, Center City, King of Prussia, and Washington, D.C.

Pizzeria Vetri, in turn, will send its marinara sauce, mozzarella and basil to Shake Shack, which will convert its fried chicken sandwich into a Chick'n Parm ($6.99). This will be sold at the Shake Shack locations in Center City, University City, and King of Prussia Mall.

More on the rotolo? Watch this: