BERLIN  — Angela Merkel is expected to name Ursula von der Leyen as her new defense minister when she presents her cabinet list on Sunday, a surprise choice that could vault the ambitious ally into the lead as the front runner to succeed the chancellor.

Merkel, 59, will begin her third term on Tuesday — three months after winning the September 22 election — after her junior coalition partners, the Social Democrats, voted on Saturday to join her in a "grand coalition."

Even though the normally cautious Merkel has an aversion to the unexpected, she pulled a rabbit out of her hat in picking the spirited von der Leyen to lead the defense ministry, one of the top jobs in her cabinet with one of the biggest budgets.

Merkel has no designated successor and has denied speculation she would step down midway through her next term. But the remarkable turn of events for von der Leyen will revive all that if the 55-year-old manages to master the male-dominated bastion as Germany's first woman defense minister.

"Those who know von der Leyen know she's got the toughness needed for the difficult job," wrote Bild am Sonntag columnist Michael Backhaus on Sunday. "Merkel showed a lot of courage picking von der Leyen, courage she lacked in the negotiations."

Von der Leyen is a controversial figure in the conservative wing of Merkel's Christian Democrats for openly defying the chancellor on women's rights. She wanted to be Foreign Minister but it went to the SPD as did her current job, Labor Minister.

A trained gynecologist who served as Family Minister in the first "grand coalition" with the SPD from 2005 to 2009, von der Leyen reportedly turned down Merkel's initial offer to lead the lowly Health Ministry — a risky gambit that paid off.

On Saturday speculation in Berlin was first rampant that she would be Interior Minister before reports later emerged that she would replace Thomas de Maiziere as Defense Minister.

MERKEL'S OTHER CABINET PICKS

Fluent in English and French, von der Leyen his among the CDU's most popular politicians despite the animosity from its conservative wing for her efforts to modernize the party. Proposals for a formal, binding quota for more women in top positions in companies, for instance, have drawn criticism.

Her popularity stems from an engaging speaking style, down-to-earth manner and the determined way in which she has pushed the CDU towards the center. Her signature issue was creating more childcare facilities in a country of stay-at-home mothers.

A mother of seven who was born in Brussels and lived in Britain and the United States, she grew up surrounded by politics. Her father Ernst Albrecht was a CDU state premier for Lower Saxony from 1976 to 1990. A rarity in German politics, she came to it late when she was 42 after a career in medicine.

Merkel also surprised Germany four years ago by picking Wolfgang Schaeuble as Finance Minister, a post the 71-year-old is widely expected to retain as one of the country's most popular post-war finance ministers.

Her other cabinet picks due later on Sunday evening include: de Maiziere as Interior Minister, Hermann Groehe as Health Minister, Johanna Wanka will stay as Education Minister and Peter Altmaier will become her chief of staff.

The CDU's Bavarian sister party, the Christian Social Union (CSU), is expected to name Alexander Dobrindt as Transport Minister, Hans-Peter Friedrich will be Agriculture Minister and Dagmar Woehrl as Development Minister.

SPD chairman Sigmar Gabriel formally announced the six SPD ministers on Sunday: Gabriel himself will be Economy Minister and Vice Chancellor, Frank-Walter Steinmeier will be Foreign Minister, Andrea Nahles will be Labor Minister, Heiko Maas will be Justice Minister, Manuela Schweisig will be Family Minister and Barbara Hendricks will be Environment Minister.