A woman arrested on suspicion of attempted murder has been released on bail.
Police were called to a house in Hoe Street, Walthamstow, at just after 2pm on Saturday following reports of a man suffering from a stab wound to the chest.
The man in his 20s was treated at the scene by paramedics and taken to Whipps Cross University Hospital, where he remains in a serious but stable condition.
The 23-year-old woman arrested in connection with the stabbing has been bailed to return to an east London police station in mid May.
London ambulance service (LAS) and London Air Ambulance (LAA) attended the scene and treated a man in his 20s.
London Air Ambulance (LAA) attended the scene and a video can be seen here of it landing in the grounds of the Latter Day Saints Church in Hoe Street, Walthamstow.