Premise: Summer Lovers is a 1982 American romantic comedy film written and directed by Randal Kleiser, starring Peter Gallagher, Daryl Hannah and Valerie Quennessen. It was filmed on location on the island of Santorini, Greece. The original music score is composed by Basil Poledouris. "Summer Lovers" featured "Hard to Say I'm Sorry", a No. 1 hit for Chicago and "I'm So Excited" by The Pointer Sisters.
Hypothesis: Randal Kleiser wasn't considering Peter Gallagher for Summer Lovers but his friend strongly advised Randal to give Peter a try.