The 35-year-old was arrested on Friday (March 30). He was released on bail yesterday until a date in May, the BBC reports.
The torso of the former EastEnders actress was discovered in Regent's Canal, near Broadway Market, east London, on March 6.
Her brother Tony was charged with her murder on March 10 following his arrest.
More body parts belonging to Gemma, who played Kerry Skinner in the BBC One soap, have subsequently been found in the canal.
Former co-stars including Dean Gaffney, Brooke Kinsella and Joe Swash have all paid tribute to Gemma since her death.