They also have given him the green light to join the clan, says the socialite's mother.
"This has honestly become the real thing," Kathy Hilton, 49, tells Vegas Luxe Life blog. "It's a great love match, and I have a funny feeling it's going to go all the way, and we've already given it our approval."
Added husband Rick Hilton, 52, about the Good Charlotte rocker: "He's the perfect example of 'don't judge a book by its cover.' He's polite, well mannered – even calls me sir. We love him like family already."
Paris, 27, and Benji, 29, returned to the U.S. after a month of touring Europe and South Africa with Madden's band. Since getting together in February, the couple have rarely left each other's sides and wear rings on their engagement fingers of the other's initials.
"Their life has never been better," Kathy Hilton tells Robin Leach, who wrote the Vegas Luxe Life blog. "We agree with Paris that he is an amazing guy... He's changed her life, and I really think she's genuinely in love for the first time."