Ms Blake (M) and her sons died from neck and head injuries, a post-mortem examination found.
The partner of former EastEnders actress Sian Blake has admitted murdering her and their two children.
Ms Blake, 43, Zachary, eight, and Amon, four, were found at the family home in Erith, London, in January after being reported missing on 16 December.
Arthur Simpson-Kent, 48, entered guilty pleas before Mr Justice Singh at the Old Bailey via video link from Belmarsh prison.
Outside court, Ms Blake's sister Ava said the family were "really relieved".
Simpson-Kent, a hairdresser, was arrested at Heathrow Airport in February after being extradited from Ghana.
Ms Blake and her sons died from neck and head injuries, a post-mortem examination found.
She played Frankie Pierre in 56 episodes of EastEnders between 1996 and 1997 and had been living with motor neurone disease before she died.
Simpson-Kent left the UK days after Ms Blake, and the two boys were reported missing.
Sian Blake's and Arthur Simpson-Kent's sons Zachary and Amon Four days after the bodies were found, he was arrested on a beach in Ghana by local police.
The arrest came after locals recognised him from a photo shared on social media and tipped off the authorities.
The EastEnders actor appeared in the 1998 film Siberia and TV movie May 33rd in 2004 under her stage name Syan Blake, according to her profile on IMDB.
The Met has referred the case to the Independent Police Complaints Commission (IPCC) over its handling of the investigation.
A serious case review is also under way.
