The ITV daytime programme has had a tumultuous year after losing both of its presenters - Phillip Schofield and Holly Willoughby.
Dr Ranj left the show in 2021 and later said the "culture at This Morning had become toxic".
ITV's chief executive has previously said she "did not recognise" claims of a toxic culture on the programme.
Schofield left the series in May following reports of a rift with Willoughby. A week after his exit, he admitted having an affair with a younger colleague.
Willoughby returned to the show, but left in October. The programme is currently being hosted by guest presenters.
At the time of Schofield's affair, which dominated the headlines, some former staff including Dr Ranj raised wider concerns about a toxic work environment they claimed to have experienced on the show.
"Some days [I had] done a night shift and gone straight into the studio and done something because I loved it so much," he said.
"And then I was doing stuff behind the scenes as well because I felt passionately about so many of the values that we were doing across the channel - diversity and pride stuff, you know, anti-bullying stuff."
But Dr Ranj left the show two years ago. "When it went away it was really painful," he said.
From BBC