Brighton Kemptown MP Lloyd Russell-Moyle is to resign his East Brighton seat on Brighton and Hove City Council.
Mr Russell-Moyle, 31, was elected to the House of Commons at the general election in June with a majority of almost 10,000.
He won his parliamentary seat just 10 months after winning a by-election to represent the council ward that includes Whitehawk.
But he has written to fellow Labour Party members to say that a selection timetable has been agreed even though he has not yet resigned.
He and his party colleagues are keen to have a candidate in place when he resigns from the council in the coming weeks.
Mr Russell-Moyle is expected to resign formally in the final week of the year or, at the latest, during the first week of 2018.
The by-election to vote in a new councillor is likely to take place on Thursday 1 February or Thursday 8 February.
The new councillor should then be able to take part in the debate and vote on the council’s budget for the coming year.
Candidates have until next Thursday (14 December) to put themselves forward, with the hustings and selection meeting scheduled for a week later (Thursday 21 December).
Mr Russell-Moyle said: “It is a real honour to represent you as one of your local councillors as well as your newly elected Member of Parliament.
“I have thoroughly enjoyed my time representing my home ward on the council and working with the Labour group to deliver for the people of East Brighton.
“The general election in June was completely unexpected but thanks to the hard work of our members like you, I became your Member of Parliament.
“However, I believe that now is the time to hand over the reins as your local councillor to someone that can dedicate the time and energy to our local area – to someone who has the track record, the passion, someone who know the area like the back of their hand, someone that will support our schools, adult social care, youth work.“The council has achieved a lot in the last few years, including building hundreds of new council homes, this week signing the first ever union agreement between the council and the unions, saving youth services and much more.
“We need the strongest candidate possible if we are to keep up the good work.”
The early favourite to win the selection is Nancy Platts, who stood for the Brighton Kemptown seat at the 2015 general election and for Brighton Pavilion in 2010.