Palladium hollywood adele concert Joe Jonas  Delta Goodrem

Nick Jonas and girlfriend Delta Goodrem are both singers, but they took in someone else's music Wednesday night -- Adele!

The couple, together since May, attended the singer's concert at the Hollywood Palladium Wednesday night and looked so happy! Nick, 18, held Delta's hand as they made their way through the packed crowd, and Delta, 26, couldn't stop smiling!

Nick and Delta vacationed in Bali together in June and Nick introduced her to his family in July. Things are getting serious ...