The 18-year-old singer - who has previously romanced Miley Cyrus and Selena Gomez - began dating the Australian popstar in May and now things are getting so serious, the 26-year-old beauty has now met his mother Denise and younger brother Frankie.
According to website X17 Online, Nick took Delta to Beverly Hills restaurant Villa Blanca, where they enjoyed a meal with Denise and Frankie.
As they left, Nick also bought Delta a rose and helped her into their car first.
The pair were first linked in May after they were spotted leaving the ArcLight cinema in Los Angeles hand-in-hand.
Nick - who is currently working on his solo career - later tweeted: "I feel so blessed. Had a great weekend."
Delta split from fiance Brian McFadden in April after a six-and-a-half year relationship with the couple claiming they had "grown apart".
A statement released by their publicist at the time said: "Delta Goodrem and Brian McFadden regretfully announce that they are no longer engaged, and after much consideration, have mutually decided to end their relationship."
As they do every summer, the Martin family relocate to their summer home over the...