Drivers on the Central Line will strike for two days just before Christmas as a dispute between unions and Transport for London (TfL) rumbles on.
Members of the Rail, Maritime and Transport Union (RMT) will walk-out from 8pm on 21 December to 2am on 22 December.
Strike action will resume at 4am on the 22 December before ending at 8pm.
The union claims the action is "over a comprehensive breakdown in industrial relations".
London Underground director of line operations Nick Dent said: "The further strike action called by RMT remains totally unjustified.
"They are demanding the reinstatement of a driver who was sacked for failing a drugs test, something for which we have zero tolerance.
"We always strive to run a reliable service but our commitment to the safety of both customers and staff is absolute and something we will never compromise on.
"I urge the unions to call off this entirely unnecessary strike action which will only cause disruption to our customers during the festive period.”
The line ground to a halt earlier this month as drivers staged industrial action over the sacking of two drivers following alleged safety breaches.
RMT general secretary Mick Cash said: "Our members have shown just how angry they are at the abject failure of management to sort out long-standing problems along the line in the rock-solid action earlier this month and LU have now had plenty of time to resolve the issues but have chosen to bury their heads in the sand."