Angelina Jolie treated boyfriend Brad Pitt to a tour of a famous house built by his architectural idol FRANK LLOYD WRIGHT for his upcoming birthday. Pitt turns 42 on 18 December (06) and Jolie surprised him with a trip to Wright's masterpiece, Fallingwater, in Pennsylvania on Thursday (07DEC06). Jolie and the OCEAN'S ELEVEN star, who is an architecture buff, took a two-hour guided tour and then held a private birthday party in Fallingwater's living room. CARA ARMSTRONG, the house's curator of education, who led the couple on their tour, said, "Brad said he had wanted to experience Fallingwater ever since he took an architectural history course in college. He and I talked quite a bit about design and art. He was incredibly well informed about architecture." Armstrong told the Pittsburgh Post-Gazette newspaper the celebrity couple were "very gracious and very engaged in the house. As we say in the Midwest, you could tell their mothers raised them right." The famous house, in Fayette County, Pennsylvania, about 50 miles (80 kilometres) southeast of Pittsburgh, is built over the wooded Mill Run creek. After the tour, the couple headed to the living room to enjoy champagne and caviar, which Jolie had arranged to have sent in and later invited the staff to join them. Jolie told Fallingwater staff members that selecting a birthday gift for Pitt was challenging, adding, "He's so hard to buy for."