Industrial action affecting all underground lines is due to start at 18:30 BST.
London Underground (LU) has warned commuters there could be no services at all on Thursday as a result of the walk-out.
The strike was called after LU and unions failed to agree a pay deal over new Night Tube services.
The weekend services are set to begin on 12 September on sections of the Central, Jubilee, Northern, Piccadilly and Victoria lines.
There are concerns some employees will have to work more overnight shifts and may have to work on their own in some stations.
Transport for London (TfL) said extra buses, river boats and Santander Cycles would be provided during the strike.
However, it warned that roads and public transport would be much busier than usual and advised travelling outside normal rush-hour periods.
Commuters have been advised to complete any Tube journeys by 18:00 BST.
Passengers using First Great Western services will also be hit by a 48-hour Rail, Maritime and Transport (RMT) union strike from 18:30 BST, which is expected to disrupt long-distance services in the west of England, Wales and those in and out of Paddington.
Workers involved in the two disputes will stage a rally outside Paddington just before the strikes start.
Around 20,000 Tube workers are expected to walk out.
Members of the RMT, Transport Salaried Staffs Association (TSSA), and Unite plan to begin their strike at 18:30 BST.
Aslef drivers will begin strike action from 21:30 BST. No further negotiations are planned ahead of the action, according to RMT.
On Monday, unions rejected LU's latest pay deal, which it said was an increased but "final" pay offer made "in an attempt to conclude five months of talks".
It included a 2% rise this year and £2,000 for drivers on the weekend night Tube service.
Mayor of London Boris Johnson told the BBC: "What we've done is made an extremely good offer, that I think most Londoners would think was more than handsome."
Unions would "not succeed" in their aims, he said, and urged them to accept the pay offer, which he described as "final".
He said it was "absolutely wrong to hold London to ransom" and apologised for the disruption which he warned would be "very considerable".
After further talks on Tuesday, RMT general secretary Mick Cash, said "despite strenuous efforts by union negotiators the.... action is on" and "there are no further talks planned at this stage", ahead of the strike.
Finn Brennan, Aslef's organiser said the responsibility of the strike "rests squarely with London Underground management" who "squandered the window of opportunity" to resolve it.
The TSSA union also rejected the offer and general secretary Manuel Cortes said: "This dispute is not just about pay, but about how to run a safe and secure night Tube which serves the passengers as well as rewarding the staff."
Talks are set to resume on Friday.
Labour leadership contender Jeremy Corbyn has tabled a Commons motion expressing dismay at the "disgraceful" treatment of Tube workers.
He has called on Mr Johnson to withdraw the "imposition" of night working.
The motion states that uncontrolled and unmanaged night work can have a serious impact on the physical and mental health and well-being of staff as well as a detrimental impact on family and social life.
Getting about, Transport for London (TfL) advice
- Cycle and walk where possible
- Extra bicycles will be available to hire from London's cycle hire scheme in central London
- The DLR, London Overground, bus network, tram and TfL Rail services will operate as normal, however passengers are advised to travel outside of morning and evening peak times on Thursday
- First Great Western staff are striking too - there will be no First Great Western service between Paddington and Greenford for 48 hours from 18:00 BST on Wednesday as a result of separate strike action
- Chiltern Railways services are not stopping at stations between Marylebone and Great Missenden travelling southbound during morning peak time, and northbound during evening peak times
- Chiltern Railways services between Aylesbury and London Marylebone via Amersham are also affected by the lack of LU signallers on Wednesday night and Thursday
- Up to 200 extra buses will operate on key routes
- The congestion charge remains in place