Patrick Schwarzenegger's sister happy for him, Miley Cyrus

Patrick Schwarzenegger's older sister Katherine says he and his singer girlfriend Miley Cyrus are "adorable".

Katherine, 25, said she loves seeing her 21-year-old brother happy, reported Us magazine.

"You just want your sibling to be happy. If they're with someone who makes them happy and in a happy healthy relationship then I'm happy," she said.

Katherine's family, including her famous parents Arnold Schwarzenegger and Maria Shriver, are reportedly equally as welcoming when it comes to the 22-year-old "Wrecking Ball" singer.