Well, well, well. Someone's been busy!
The couple was spotted around town at the beginning of July and have been going on romantic dates with each other down at the beach in Malibu and dining out at Nobu.
Costello works for Penn's J/P Haitian Relief Organization and also worked on the documentary Waiting for Superman, as well as some future projects with Ron Howard.
Hopefully this one's a keeper for ya, Sean!
[Image via WENN.]