A popular former Israeli military chief jumped into the political fray Thursday, announcing he would run for office in the upcoming election and instantly injected perhaps the strongest challenge to Prime Minister Benjamin Netanyahu's lengthy rule.

Retired Lt. Gen. Benny Gantz has been polling favorably in recent weeks, emerging as a fresh, exciting face in Israel's staid political landscape. By officially registering his new party, "Israel Resilience," Gantz shakes up a snap three-month election campaign that has been widely seen as Netanyahu's to lose.

Even before officially entering the fray, several polls showed Gantz's hypothetical party coming in second only to Netanyahu's ruling Likud in the run-up to the April 9 vote.

Gantz has yet to comment publicly on the party and was not expected to make any statement Thursday.

Though Gantz has yet to lay out his worldview or political platform, he flaunts stellar military credentials — a must in security-centric Israel — and a squeaky-clean image to contrast Netanyahu's corruption-laden reputation.

While still short of the kind of widespread support likely needed to become prime minister, his candidacy captures a yearning in Israel for a viable alternative to emerge against the long-serving Netanyahu, seeking his fourth consecutive term in office.

With a commanding lead in the polls, and a potential indictment looming against him, Netanyahu called early elections this week, seeking to pre-empt corruption charges and return to office to become the longest serving premier in Israeli history.

Police have recommended charging Netanyahu with bribery and breach of trust in three different cases. Netanyahu has denied any wrongdoing, dismissing the allegations as a media-orchestrated witch hunt aimed at removing him from office.

Even with Netanyahu's legal woes, Israel's established opposition parties have remained splintered and have been unable to produce a viable challenger. Gantz seems to be taking votes away from all the major parties and may not tip the scales away from Netanyahu just yet. But the emergence of the tall, telegenic ex-general with salty hair makes things more interesting, as he could spark new alliances with other moderate parties to give the hard-line Likud a good fight.

"It's too early to tell, but he definitely strengthens the center-left camp," said Mina Tzemach, a leading Israeli pollster, whose most recent survey gave Gantz's new party as many as 16 seats in the 120-seat Parliament. "He projects security and integrity. And the fact that he looks good doesn't hurt either."

Gantz, 59, was a paratrooper who rose up the ranks to command special operations units and other various units before becoming Israel's 20th military chief between 2011-2015. His term was marked by two wars with Hamas militants in Gaza and a covert air campaign in Syria against Iranian arms shipments to Hezbollah guerrillas in Lebanon. Since his discharge, he's been highly coveted by several Israeli political parties.