The LVMH and boss has invested in eponymous brand. The 27-year-old French designer was at one point rumoured to be in the running for the top job at Dior, alongside a number of more experienced candidates.
The scope of Arnaults investment in Simoens brand has not been disclosed, but insiders confirmed the acquisition.
They do believe in him, and want to finance him, one source told WWD, suggesting that Arnault could view Simoens as an eventual candidate for a job with a bigger luxury brand.
The move represents a departure from Arnaults recent acquisitions. Most recently, the luxury titan spent $6bn to acquire Bulgari; he has also built a sizeable stake in . His last investment in an untested fashion brand was in 2009, when LVMH purchased a 49% stake in Ali Hewson and Bonos Edun.
Simoens worked for designers including , , and before shifting his focus to his own brand. He recently concluded a collaboration with French fashion brand Leonard, saying the departure left him free to concentrate on new projects.
His famous fans include Blake Lively, Rachel McAdams and Beyonce. The singer chose a purple mini-dress by Simoens for the cover of the deluxe edition of 4, her most recent album.
Learn more about Raf Simons' move to Dior
Read about the rise of Raf in our profile from the May 2009 issue