In a statement on Monday ahead of the announcement, a spokesperson for Wynne said: "This is the cabinet Kathleen wanted and always planned on."
The expected appointment of Sousa, the MPP for Mississauga South, to the finance post being vacated by Dwight Duncan may be seen by many as the result of his endorsement of Wynne at the leadership convention.
Wynne's spokesperson also added that the premier-designate feels Sandra Pupatello "has lots to offer," but her leadership rival "is still considering her options."
Wynne's new cabinet will be officially announced Monday afternoon, but details started to leak on Sunday evening.
Government sources have also told CBC News that Ottawa West-Nepean MPP Bob Chiarelli will take over the energy portfolio, while Toronto Centre MPP Glen Murray will be the minister of transportation and infrastructure.
Like Sousa, Murray had also sought the leadership of the Ontario Liberal Party. But he dropped out of the leadership race ahead of the convention and threw his support behind Wynne.
Wynne will also put first-time cabinet minister, Guelph MPP Liz Sandals, into the education portfolio, while Education Minister Laurel Broten will become the minister of intergovernmental affairs.
Sandals served as the head of a local school board and also as the president of the Ontario Public School Boards' Association, prior to being elected as an MPP in 2003.
The governing Liberals have hit a rough patch in their relationship with the province’s public teachers after using controversial legislation to impose contracts upon them.
Yasir Naqvi, MPP for Ottawa Centre and the president of the Ontario Liberal Party, will enter cabinet as the new labour minister. He has also not previously served as a cabinet minister.
Government sources also say that Health Minister Deb Matthews will keep her portfolio.
Matthews had supported Wynne during her leadership bid.
Wynne officially becomes the premier of Ontario on Monday. She has promised to serve as the province’s agriculture minister at the same time.
The incoming premier and her cabinet are due to be sworn in at the legislature at 3 p.m. ET. Wynne is expected to speak to the media later in the afternoon.
Prominent ministers leaving cabinet
Several cabinet ministers who served under Premier Dalton McGuinty have announced their exit from the provincial government.
Duncan, the longtime finance minister, announced last week that he will resign from his Windsor — Tecumseh seat on Thursday.
Energy Minister Chris Bentley, the MPP for London West, has also stepped down. His resignation also takes effect on Thursday.
Northern Development and Mines Minister Rick Bartolucci says he won’t run again in the next provincial election and he no longer wants to be in cabinet.
McGuinty announced his intention to step down as leader of the Ontario Liberal Party last fall.
He agreed to stay on until the party chose a successor.
Wynne won the party leadership at a leadership convention in Toronto late last month. When she is officially sworn in on Monday, she will be the first female premier in Ontario's history.
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