Since Greenhalgh and Bohuslavova formed Vital two years ago, the pair have produced ads for Powergen, Lego, Hoover, Pizza Hut, Maltesers, Sky Sports, npower, Morrison's and Holsten.
Before its UK launch as a production company, Vital Prague, founded by Bohu-slavova, was an established service company.
Greenhalgh said: "Vital has given Ivana and I an identity and presence. But this move will hopefully take us to another level and allow us to experiment."
Mary Francis, The Paul Weiland Film Company's managing director, said: "Jon and Ivana can retain their independence, while we can widen our offer of directors. We will enjoy having them around."
Greenhalgh started his career as an art director at WCRS. He also had stints at Chiat\Day, Saatchi & Saatchi and BMP DDB before becoming a director.
During his decade-long directing career, he has been represented by RSA, Godman, Stark and Large.