Mars kicks off the song with a little ode to Pitt, "You might have seen him in Fight Club. You might have seen him in Inglourious Basterds. Benjamin Button."

Mars goes on to repeat Benjamin Button a few more times. "I really like Benjamin Button," Mars informed he crowd. But the best part is when Mars ad-libs at the 1:09 mark, "Brad Pitt you sexy motherf-er." It's like it should have been part of the song's lyrics all along.

According to Vanity Fair, Pitt was there as the host of a gala for the Make It Right Foundation, which provides affordable and eco-friendly housing for people in need.