The lovebirds who have only been dating for six months were first spotted out together in December when they attended Courteney's close pal Jennifer Aniston's holiday party in Los Angeles.
Suspicions were raised that things were moving very fast when the couple's friend Ed Sheeran - who introduced them to one another - spilled the beans about them moving in together in April.
Johnny, 37, and his band collaborated with the 'Cougar Town' star on her directorial debut, 'Just Before I Go', and he opened up about his relationship with the actress for the first time at the film's premiere.
The Northern Irish guitarist gushed: "Courteney is the most completely confident person I've ever met - at everything. She gets music. She gets art. She gets the way a scene gets constructed, the way dialogue works.