Mr Birtwistle, who lost his Parliamentary seat in 2015 to Labour's Julie Cooper, revealed to the Burnley Express he had already been selected as the Lib Dem candidate should a snap General Election be called before May 31st this year.
Prime Minister Theresa May shocked the nation when she announced that a General Election would be held on June 8th, a decision which means that Mr Birtwistle is the automatic candidate for the Burnley and Padiham constituency.
He said: "I was as shocked as everyone else. I was actually out canvassing and had my phone on silent so I didn't hear the news until later. My phone hasn't stopped ringing.
"The Liberal Democrats decided last year on the candidates for our target seats and I was chosen. I didn't think an election would be held so soon but I'm looking forward to it."
Mr Birtwistle, who at 73-years-old would be one of the oldest MPs in Parliament should he be voted in, currently sits on Burnley Borough Council and is a candidate in the Lancashire County Council elections to be held in May.
He added: "I'm 73 but I feel more like 60. I'm doing 15,000 to 20,000 steps a day canvassing but I might have to up that in the coming weeks. If I was voted in as MP I would have to look at dropping one of my other responsibilities."
Mr Birtwistle also said he is looking forward to the challenge of resuming his head-to-head battle with Labour's Julie Cooper who will be seeking re-election.
The two, who both still sit on Burnley Council, first stood against each other for Parliament in 2010 when Mr Birtwistle was victorious, but Mrs Cooper was elected two years ago with 14,951 votes to Mr Birtwistle's 11,707.
He added: "I lost a lot of votes in 2015 to UKIP, but I'm sure they will be as potent this year post-Brexit. I will be printing my leaflets with all my achievements on one page and the other page with Julie Cooper's achievements will be blank."