The Belgian designer was named artistic director at The Fashion house earlier this month and the company are delighted to have him on board.
Dior president and chief executive Sidney Toledano told WWD: ''It's a very exciting time. I always said that the right person would come along when all the stars aligned and that's exactly what happened last week.
''Simons has already begun to lay out his vision for where he can take Dior in the future and I think we are all very excited by that vision.''
Raf - who will show his first collection for Dior in July - recently insisted his designs will not be ''only'' minimalist.
the former Jil Sander designer said: ''I don't think it's wrong to call me a minimalist. It's wrong to call me a minimalist only.
''I am also a romantic person.
''I'm interested in creativity, the Evolution of creativity and the relationship between creativity and the times we live in.
''When I'm married to a house, I will fully embrace its original intention, its original heritage and meaning. I wouldn't go to that place if I only had minimalism in mind. I'm very aware of what the environment is about.''