Nandy, who represents a Leave constituency and had criticised calls for a second referendum on Britain’s EU membership, made the revelation in a letter to Friday’s Wigan Post – her local paper.
She wrote: “Without what were once our Labour heartlands, we will never win power in Westminster and help to build the country we know we can be.
“I have heard you loud and clear when you said to earn that trust means we need a leader who is proud to be from those communities, has skin in the game and is prepared to go out, listen and bring Labour home to you.”
Nandy, who has been an MP since 2010 and co-founded the Centre for Towns think tank, joins Sir Keir Starmer and Jess Phillips – who also announced her candidacy today – on the ballot paper.
Rebecca Long Bailey, seen as the favourite of Corbyn supporters, has been knocked into second place among the party as a whole by Starmer, according to a YouGov poll, but has yet to formally launch her own campaign.
Nandy is seen as the outsider, with just 5% of those polled backing her.
Delivering Brexit, she said in her pitch, should not mean “turning our backs on decency, tolerance, kindness”.
“It breaks my heart that in this election so many of you felt you had no choice but to vote for a Tory party that has sent a wrecking ball through our community over the last decade,” she wrote.
Speaking to HuffPost UK in August, Nandy urged the party to reconnect with voters outside the Westminster bubble – and to compromise.
“What matters the most, actually, is that we build a settlement that works for people, and we build settlement that lasts,” she said.
“Clement Attlee is often seen in my party is the best prime minister we ever had. But how did he build that settlement that outlasted him and several governments after him, and completely reshaped the way that Britain works?
“Well, I can tell you, honestly, he didn’t build it by holding rallies and talking to himself. He didn’t build it by doing interviews with Daily Telegraph of the Times, or even the Guardian.
“He built it by going out and reaching out to people who absolutely did not agree with him, and trying to work out what sort of consensus was possible.”
Nandy held her seat with a reduced, but comfortable, majority of 6,728 votes in December’s election. It had been more than 16,000.
The Brexit Party won nearly 6,000 of Wigan’s votes. Some 63% voted to Leave in 2016.