Track closures and engineering works have triggered warnings of a “Tube meltdown” on the day of the Royal wedding.
Transport for London bosses have been summoned to City Hall on Wednesday to explain the decision to carry out works on Saturday.
As well as Prince Harry and Meghan Markle's wedding, the day also coincides with the FA Cup final between Chelsea and Manchester United at Wembley.
Despite the major events, TfL is planning to carry out works on Saturday and Sunday, leaving two major lines partly closed.
The District Line will be shut between Edgware Road and South Kensington, as well as Richmond, Wimbledon and Ealing Broadway services to South Kensington.
The Circle Line will also be shut between Aldgate and Edgware Road all weekend, and there will also be closures on part of the London Overground.
City Hall’s transport committee now says it plans to quiz TfL bosses on how they plan to avoid a "Tube meltdown" as thousands of people flock to London during the weekend.
But TfL said the impact would be limited.
“The vast majority of our services will be running as normal on the weekend of 19/20 May, helping everyone enjoy the royal wedding and the FA Cup Final,” said London Underground’s director of network operations Nigel Holness.
“There are some closures on the District and Circle lines due to essential upgrade work and on London Overground due to Network Rail track work.
"I advise customers to check their best route by using our website and social media channels for live traffic news and service updates.”
