This is what happened with Tom Petty's "Runnin' Down a Dream," a track from his 1989 solo album Full Moon Fever. Despite it being a solo project, Petty still enlisted the help of Heartbreakers guitarist Mike Campbell, and it was he who first came up with that descending guitar riff. "I liked the lick a lot, and I'd sit around, playing it on my guitar, experimenting with it in different ways," he recalled for 2005's Conversations With Tom Petty. READ MORE: The 'Big 4' of Tom Petty AlbumsCampbell may not have blinked or moved, but apparently he did notice Lynne's face. READ MORE: Tom Petty Album Opening Songs RankedAnd Campbell didn't have to try that hard to make the moment happen.