The Workers' Party (WP) will have a new leader by the time Parliament reopens in May after its mid-term break.
The party is holding its leadership elections early - on April 8 - to elect its secretary-general.
This means that for the first time in nearly two decades, Mr Low Thia Khiang will not be at the helm of the opposition when the second half of this parliamentary term begins.
The 61-year-old said last November he would be stepping down as WP secretary-general - a position he has held for 17 years - to make way for new blood.
In a statement to The Sunday Times yesterday in response to queries, WP chairman Sylvia Lim said: "Since the Prime Minister announced that Parliament would be prorogued in April and start a new session in May, it makes sense for the WP to start the new session of Parliament with the new secretary-general."
This is the earliest the WP has held its biennial Central Executive Council (CEC) elections in over a decade. Five of the past six were held between June and August. The last one, in 2016, was in May.
The Sunday Times understands that Mr Low may ask the Speaker to allow the new secretary-general to take up his current seating position when Parliament opens.
As opposition chief, Mr Low now sits across the aisle from Deputy Prime Minister Teo Chee Hean. He is the only opposition MP to have a seat in the front row opposite the Cabinet ministers.
Observers say the WP's move to hold its elections early is symbolically significant.
Institute of Policy Studies deputy director Gillian Koh said: "The new session is an opportune moment to brand the party under a new leader, especially with a major Cabinet reshuffle expected after the proroguing."
Prime Minister Lee Hsien Loong had said Parliament would be prorogued after the Budget session, which starts on Feb 19.
During the break, there will be a Cabinet reshuffle during which the People's Action Party's fourth-generation leaders are expected to assume more major roles.
The new parliamentary session in May will see other firsts, including President Halimah Yacob's inaugural address laying out the Government's agenda for the remaining term.
The front runner to take Mr Low's place is Mr Pritam Singh, 41, now the party's assistant secretary-general - although this is by no means a foregone conclusion. Party cadres will vote via secret ballot for the posts of chairman, secretary-general and members of the CEC.
In 2016, MP Chen Show Mao, 57, surprised many by challenging Mr Low for the top job. Mr Chen lost with 45 votes to Mr Low's 61. It is not clear if Mr Chen will make another bid for the position.
Nominations take place only on the day of the election.
Political observer Lam Peng Er said other contenders for secretary-general could include younger WP Non-Constituency MPs Dennis Tan, 47, and Daniel Goh, 44.
One consideration cadres might have is the ongoing Aljunied-Hougang Town Council (AHTC) civil suit against the WP MPs, said Dr Koh. Mr Low, Ms Lim and Mr Singh are being sued by an independent panel representing AHTC.
If so, cadres may want to hand the position to an NCMP who "isn't under that cloud", she added.
Regardless of who takes over, the move to elect a leader early is a signal that the WP is committed to leadership renewal, said the observers.
Said Dr Lam: "This generational change will give WP greater resonance among younger Singaporeans and help them to recruit more credible, young candidates."
Added Dr Koh: "Naming a new secretary-general ahead of Parliament's new session is a grand gesture that the WP is doing something fresh and new."
