UFC 189: Mendes vs. McGregor was a mixed martial arts event held on July 11, 2015, at the MGM Grand Garden Arena in Las Vegas, Nevada.

José Aldo da Silva Oliveira Júnior, known as José Aldo, is a Brazilian professional mixed martial artist and professional boxer who currently competes in the Bantamweight division of Ultimate Fighting Championship (UFC) after previously competing at Featherweight, and was the fourth and final WEC Featherweight Champion. He became the first UFC Featherweight Champion following the UFC/WEC merger. Aldo is often regarded as one of the greatest mixed martial artists of all-time, and is considered to be the greatest featherweight of all time after defending his UFC title seven times and his WEC title twice.