The body of the former EastEnders was found on March 6, 2012. Her 35-year-old brother was arrested the following day and charged later that week with her murder.
Tony was due to stand trial for his 29-year-old sister's murder on November 12.
Today (September 28) at the Old Bailey he accepted responsibility for her death and he will now face trial on January 14, where it will be decided whether his crime was murder or manslaughter.
A severed head was found in Hackney canal earlier this month near where the headless torso was originally recovered. It was soon after confirmed to be Gemma's.
Gemma played the role of Kerry Skinner in EastEnders in 2000 and 2001.