Israel's first Prime Minister, David Ben-Gurion, was from the Mapai party. That party went on to become Labor, including a period as part of the "Alignment" alliance. In 1977, Menachem Begin, leader of Likud, became the first Prime Minister to not be from Labor.
In 2001, Ariel Sharon, Likud leader and Prime Minister, founded Kadima, while in office. After his strike, Ehud Olmert took over as Kadima leader. He too, was from Likud.
Today, a third party enters the list.
Yair Lapid has informed the President that Naftali Bennet is to become Prime Minister.
Bennett has never served as an MK (member of parliament) for any party except the one's he has lead. While a member of Likud from 2005 to 2008, he never was elected to office under that party's banner.
There is still a chance it can all go wrong. The new government has a week or so (12 days it seems) to pass a vote of confidence. Should they fail, new elections will be held.
Once they take office, the new Knesset will look like this:
17 - Yesh Atid (left-centre)
8 - Blue and White (left-centre)
7 - Yamina (right-wing)
7 - Labor (left-wing)
7 - Yisrael Beiteinu (right-wing)
6 - New Hope (right-wing)
6 - Meretz (left-wing)
4 - Ra'am (arab, right-wing)
MAIN OPPOSITION - 52
30 - Likud (right-wing)
9 - Shas (orthodox)
7 - UTJ (orthodox)
6 - Zionist (right-wing)
6 - Joint List (arab, left-wing)
This government will be difficult to manage, presuming it does indeed manage to pass.
There are still details to work out between all the parties.