In a surprise move, Frieze art fair announced on Thursday that in 2015 Victoria Siddall will become director of Frieze London and Frieze New York.

The fair’s co-founders, Amanda Sharp and Matthew Slotover, the current directors, said that the appointment of Ms. Siddall, who will also retain her position as director of Frieze Masters, will “give us the opportunity to focus on the future and to explore new projects for Frieze.”