Labour Party members will choose the candidate for the Batley and Spen by-election.
The party sent an email to members on Tuesday informing them that the selection process had begun, with the successful candidate due to be announced on September 23.
Those interested in becoming the next MP who have been a member for at least 12 continuous months can apply by Friday at noon.
Tracy Brabin, a TV actress known for her roles in Eastenders, Coronation Street and Emmerdale, who was rumoured to be considering standing last month, appears to have already put her name forward after changing her Twitter handle to @Tracy4MP.
The seat became vacant following the killing of Labour MP Jo Cox in Birstall on June 16.
She was shot and stabbed outside the town library, where she was due to hold a constituency surgery.
According to the email, interviews will take place in London on September 19.
Shortlisted candidates will then be invited to a hustings meeting in the constituency on the evening of September 23 where local members will select the candidate.
The results of the Labour leadership election will be announced the following day in Liverpool, where the party will open its annual conference on September 25.
Commenting in the email, Paul Nicholson, the party’s regional Yorkshire and Humber director, described the widespread shock at Ms Cox’s death.
He said: “Batley and Spen experienced a tragedy that shocked people here and across the world, and left all of us mourning the wonderful Jo Cox.
“She was everything you could have asked for in an MP, working hard every day to represent the people in the constituency she served, getting things done locally and putting hugely important domestic and international issues on the agenda in parliament.
“We all miss her terribly and our thoughts remain with her husband Brendan, her small children and her family here in the constituency and further afield.
“It won’t be a by-election like any other for a number of reasons, including that the Conservatives, Lib Dems, Greens and UKIP have all said they will not be standing a candidate.
“Therefore the Labour Party has a great responsibility to select someone capable of representing all constituents across Batley and Spen.
“This will be a by-election which none of us wanted, none of us will relish contesting, but one which all of us must fight to win for Labour.”
Three right wing candidates have decided to contest the by-election.
They are UKIP member, Waqas Ali Khan, who is standing as an independent, far-right nationalist Liberty GB’s Jack Buckby and far right English Democrats’ Therese Hirst.
Members interested in standing should download an application form from https://members.labour.org.uk/parliamentary-selections and send it to Batley@labour.org.uk.
Those with queries should contact the regional office on 01924 291221.