Morgan the Agency model Danielle, now 26, first burst on to the catwalk at just 17 and spent years working full-time in the industry before going on to pursue a course in design at Griffith College.
And beauty queen Diana, who walked away with the title of Miss Universe Ireland almost three weeks ago, admits it was her sister's influence that led her to hanker after the limelight.
"My sister was a full-time model and it was something I always wanted to do as well," Diana explained.
"Having seen her modelling while I was growing up, I knew I would end up in the business some day as well.
"She was with Morgan the Agency and modelled full-time for years, but she's concentrating on college now."
Diana, who will take off for the Bahamas on August 1 to compete in the Miss Universe finals, admits her biggest fear is that she will suffer a wardrobe malfunction similar to her predecessor Lynn Kelly and that her bags won't turn up when she arrives on the paradise island.
Dublin model Lynn was hit by a bureaucratic nightmare when she arrived in Vietnam last year when one of her suitcases containing thousands of euro worth of clothes was impounded by customs officials.
Diana said: "I'm not nervous at all, other than the fear that all my bags might not get through.
"Poor Lynn, her bags didn't come through for ages, so she had to borrow dresses from the other girls there.
"She was a bit lonely over there on her own but the difference is she had five weeks over there and I'm only going to have three, so that will make it easier."
Similarly to Lynn last year, Diana will have to jet off to the Bahamas alone and will have to fend for herself when it comes to doing tan, hair and make-up.
The Assets beauty will be joined by her parents for her final week, however, although she's doubtful she will be able to spend any time with them due to her hectic schedule of events and competitions.
Diana's boyfriend, Aaron Foy, will not be joining her, because he's in Chicago.
"He doesn't really know what's going on because he's been away," she laughed. "But he's happy for me.
"He's not going to the competition but at least the time zone there will be the same so I'll be able to talk to him at regular hours."