A writ was laid in the House of Commons this morning for both the West Yorkshire vote, and one in Tiverton and Honiton in Devon, following the resignation of Neil Parish who admitted watching pornography in Parliament.
The motion was moved by Chief Whip Chris Heaton Harris, and it officially starts the countdown to polling day, which is expected to be June 23 for both contests.
Khan had the whip suspended when the allegations against him came to light in 2021.
Sir Keir Starmer will be hoping he can prove to have made progress in the crucial 'Red Wall' seat, two and a half years after Boris Johnson won his 80-strong majority during the 2019 General Election.
Labour have selected Simon Lightwood as their candidate, but the choice has sparked an internal row over the selections process, with the entire constituency executive resigning over the decision.
The Conservatives are yet to name their candidate, however sources suggested the decision could come as soon as this weekend.