Doctor Who fans will wish they had a Tardis so they could nip forward in time if Saturday's FA Cup semi final turns out to be a very close game.
Because extra time in the Manchester United and Watford match will mean a week's extra wait for the Time Lord's latest adventure.
The match which is being shown on BBC One is due to start at 5.30pm.
If there's a winner after 90 minutes of normal time, then the third episode will go ahead as planned at 7.40pm.
But if the teams are drawing, and extra time has to be played, then the showing of episode three - Gridlock - will be delayed for a week.
It will also mean that behind the scenes show Doctor Who Confidential which usually goes out on BBC Three straight after each episode will go out a week later.
Instead viewers will be given another chance to see the first episode of the first series, Rose.
Extra time in the football will also mean changes on Sunday on BBC Three, when Saturday's episode is usually repeated. If Saturday's showing is delayed because of the football, the 2005 Christmas Special The Xmas Invasion will be on instead.
It also looks extremely likely that the following Friday's episode of Totally Doctor Who will have to go out a week later too.
Official magazine Doctor Who Monthly have already had to change their schedule once because of a late change to the date this series started.
But if episode three is delayed, they'll still be out at the same time - although the team will make a few last minute tweaks to take out details of what happens in episode five because that won't have been on TV before the magazine hits the shelves later this month.