Tonight's episode will carry a tribute to her from Iain Stirling and the team.
A lawyer for Flack's family said she had taken her own life.
In a statement, Lygo, ITV's director of television, said Flack had been part of the dating show "from the very beginning" and her "passion, dedication and boundless energy contributed to the show's success".
Caroline "was very vocal" in her support of the show, and viewers "could relate to her and she to them", he said
Laura Whitmore replaced her as host of the dating show after Flack was charged with assaulting her boyfriend, Lewis Burton, last December, and had been due to stand trial. Flack denied the charge.