French billionaire Bernard Arnault will combine the Christian Dior fashion brand with his LVMH luxury goods empire as part of a 12 billion euro ($13 billion) move to simplify his business interests - a restructuring long demanded by other investors.Under a series of complex transactions, LVMH (LVMH.PA), the world's largest luxury group, will buy the Christian Dior Couture brand from the Christian Dior (DIOR.PA) holding company for 6.5 billion euros, including debt.The deal will unite the 70-year-old fashion label worn by film stars from Grace Kelly and Elizabeth Taylor to Jennifer Lawrence and Natalie Portman with the Christian Dior perfume and beauty business already owned by LVMH.The Arnault family, which holds a 47 percent stake in LVMH, will also offer to buy the 25.9 percent of the Christian Dior holding company it does not already own for about 260 euros per share, a premium of 15 percent over Monday's closing price.