Police were called just before 7am on Tuesday to reports of an injured man on the Old Kent Road on Tuesday morning.
A 47-year-old man was found with knife injuries. He died at the scene at 7.22am.
A murder investigation has been launched, led by Detective Chief Inspector Mike Nolan of the Met’s Specialist Crime Command.
DCI Nolan said: “Early indications are that the stabbing took place inside a residential address close to where the victim was found by members of the public.
“While we are keeping an open mind concerning motive, it does appear that those present at the address at the time of the stabbing were known to each other and that there is no wider threat to the public.”
Two people, a 54-year-old man and a 38-year-old woman were arrested on suspicion of murder. Both were taken to south London police stations.
On Tuesday evening police forensic examiners were still at work at the entrance to Kingsley Flats, which is part of the Peabody-owned Bricklayers Arms Estate.
DCI Nolan added: “I would like to thank everyone who came forward this morning to speak to police and local people for their patience and understanding as we go about our enquiries.
“If you have information or footage that could assist our investigation please do get in touch.”
Chief Superintendent Seb Adjei-Addoh, who leads policing in Lambeth and Southwark, said: “I know that the community will be shocked by this incident.
“Local residents will notice a more visible police presence in the area and I urge anyone who has concerns to speak with those officers as they patrol or contact your local neighbourhood police team.
“Our thoughts are with the victim’s family.”
Anyone who witnessed this incident or has information but has not yet spoken to police should call 020 8721 4622 or 101 quoting reference 891/9DEC.