Sie, who previously directed 2014 dance film sequel Step Up All In, takes over from Elizabeth Banks, director of last year's Pitch Perfect 2.
Production on the third film about an all-girl a cappella group was halted after Banks announced in June she would not return to the director's chair.
Banks, who stays on board as producer, announced Sie's involvement on Twitter.
"#PitchPerfect has a new leader," the actress wrote on Thursday, adding she was "so excited" Sie was on board.
Anna Kendrick, Rebel Wilson and other cast members of the previous films in the series are expected to return for the third instalment, due to reach cinemas in December next year.
Pitch Perfect, released in 2012, made $115m (£86.6m) at the global box office, while its sequel took $287m (£216m) worldwide.