Big-name artists don't usually perform for free these days, but that's exactly what Pharrell Williams and Robin Thicke did on Friday. The two stars hit the stage at 7 a.m. local time to perform at the annual Wal-Mart shareholders meeting in Fayetteville, Arkansas, in front of about 14,000 employees and fans.

Why did they sing for free? "Every entertainer that is here has something to do with our business," Wal-Mart spokesperson Dianna Gee told MSNBC during last year's event. "There’s some connection [to] the business, whether it’s CDs, books or T-shirts." Film studios and record labels "really work with us" to recruit the performers, she added. Last year, employees got to see equally notable stars, such as Justin Timberlake, Hugh Jackman and Tom Cruise.

Besides the performances by Williams and Thicke, as well as Harry Connick Jr. and Aloe Blacc, the event provided a platform for Walmart executives to talk about their plans for the company’s future. 

While the celebrity guests do not get paid to attend, as Walmart spokesperson Dianna Gee confirmed to MSNBC last year, they do get paid in terms of the exposure they receive for their latest projects. Not that Williams really needs it. His latest hit, “Happy,” has been highly successful, peaking at No. 1 in the United States, United Kingdom, Australia, Ireland, New Zealand and 19 other countries.