12/12/2007 AT 11:45 AM EST
How does Hilary Duff
keep conversation hot with her hockey-star boyfriend Mike Comrie? Older sister Haylie Duff spilled the beans to PEOPLE Tuesday.
"I actually caught her with a copy of the Hockey for Dummies
book," Duff, 22, said at the opening of the Foley+Corinna store in West Hollywood. Big sis says she "adores" Comrie – and says it's actually distance that makes things work between him and 20-year-old Hilary. "He lives in New York and
she lives here, and they really put in a big effort to see each other."– Shayna Arnold