Debbie Dingell, a Washington lobbyist and the wife of Representative John Dingell of Michigan, on Friday will announce her candidacy for the House seat her husband has held for 29 terms. At the beginning of the week, Representative Dingell, one of the most powerful Democrats and most popular members on the Hill, said he would retire at the end of his current term in December.

There has been speculation about Debbie Dingell’s political ambitions for a while, particularly in the past year. She is a longtime member of the Democratic National Committee, and as much a partner as any congressional wife in her husband’s political affairs.

Dingell has two months to get the signatures needed to qualify for the ballot. She is expected to make the announcement in the home district.

We spoke with John Dingell last June, asking him to reflect on his five decades in the House.