Former party leaders Nick Clegg and Ed Miliband have both announced they are to stand for re-election.
Ex-deputy prime minister Mr Clegg confirmed he would defend his Sheffield Hallam seat for the Liberal Democrats, while Mr Miliband is to run for Labour in Doncaster North.
Prime Minister Theresa May called for a general election on 8 June, which has been backed by the House of Commons.
Mr Clegg called her announcement a "grubby political calculation".
"I will be re-standing as the Liberal Democrat parliamentary candidate in Sheffield Hallam - a constituency I have had the immense privilege to represent in Parliament for 12 years - because I vehemently oppose the direction that Theresa May wishes to drag our wonderful country," he said.
"This general election is unlike any I've ever known in my political lifetime.
"Basically, the prime minister has opportunistically triggered this general election in order to secure a landslide victory so that she can impose a hard Brexit on the country, a hard Brexit which I believe is bad for my constituents here in south-west Sheffield and bad for the country as a whole."
The Labour Party has confirmed to the BBC that its former leader Mr Miliband is standing, although he is not commenting further at present.
Earlier, MPs voted in favour of Mrs May's motion by 522 to 13 in the House of Commons.
Mrs May has argued that an early general election will help the UK make a success of Brexit and provide long-term certainty.
In an interview with BBC Radio 4's Today programme earlier, she said "no politician wanted to hold an election for the sake of it" and there were risks involved in doing so.
The next general election had been set for 2020, but the Fixed Term Parliaments Act allows for one to be held earlier if two-thirds of MPs back the move.