TEL AVIV (Reuters) - Yair Lapid, a former TV anchor whose upstart political party was the biggest surprise in Israel's election, was named the country's new finance minister on Friday as a government coalition deal was signed, his spokesman said.

Lapid's centrist Yesh Atid party won a more-than-expected 19 seats in the January 22 ballot, the second most behind Prime Minister Benjamin Netanyahu's right-wing Likud-Beiteinu alliance's 31 seats in the 120-member parliament.

After nearly six weeks of negotiations, Yesh Atid agreed on Thursday to join a Netanyahu-led governing coalition. The deal, and a separate alliance between Likud-Beiteinu and the far-right Jewish Home party, were signed on Friday.

Lapid, who will replace Yuval Steinitz once a new government is sworn in, ran largely on a platform of easing the financial yoke of the middle class through the need to share the national burden - a rejection of privileges for the ultra-Orthodox. He will be forced to make steep government spending cuts and raise taxes to keep Israel's budget deficit under control.

(Reporting by Steven Scheer and Tova Cohen)