Hagar and Van Halen had actually orchestrated it all before the event. “I’d already went down and rehearsed with Ed, Al [Van Halen] and Mike [Anthony] at 5150 [Studios]. The first two records really went fast, and then it bogged down. But the chemistry at the Farm Aid thing was phenomenal.”Watch Sammy Hagar and Eddie Van Halen Perform 'Rock and Roll' at Farm AidHagar recalls that the audience had no idea what was about to hit. While they were onstage together, he announced that he would be the new lead singer for Van Halen, a moment that was both happy and bittersweet for Hagar.