After teaming up for a summer tour, Pitbull and Ke$ha have again joined forces, this time on the Miami rapper's new single, "Timber," which brings old-school Chicago blues to Top 40 radio.

The track, produced by Dr. Luke, features a thumping beat and a bluesy harmonica sample looping behind Ke$ha's vocal hook and Pitbull's rhymes. In recent years, Top 40 has been inundated with samples of whistling (Maroon 5/Christina Aguilera's "Moves Like Jagger," Flo Rida's "Whistle," Ke$ha's "Crazy Kids") and saxophones (Macklemore's "Thrift Shop,"Katy Perry's "Last Friday Night," Lady Gaga's "Edge of Glory"), so the harmonica is a welcome addition.

"Timber" is the lead single from Mr. 305's upcoming eighth studio album. The untitled LP is expected to drop in early 2014.