Simpson, 28, and Evan, 24, were spotted leaving Teddy's nightclub at the Roosevelt Hotel Monday night, July 1. The next morning, the rumored lovebirds were pictured grabbing a bite, reported Aceshowbiz.
Despite the romance rumours, a source says they were just friends.
"Evan and Ashlee have been friends for a really long time, probably ten years. They know each other from the club scene and have tons of mutual friends," a source said.
Simpson split from Fall Out Boy's bassist Peter Wentz in 2011 after three years of marriage. They have son Bronx Mowgli together. After the divorce, she dated "Boardwalk Empire" actor Vincent Piazza but called it quits last fall.