MONTREAL -- The Louis-Hippolyte-La Fontaine Tunnel has taken a multi-million dollar step forward towards getting a facelift.

Canadian Minister of Infrastructure and Communities Catherine McKenna confirmed Thursday that Ottawa is chipping in $427.7 million towards rehabilitating and modernizing the cross-river tunnel (Highway 25).

"The Louis-Hippolyte-La Fontaine Tunnel is a vital link for transportation, commerce and the economic prosperity of the Greater Montreal area," said McKenna in a release. "This major rehabilitation project will ensure the Tunnel remains efficient and reliable for years to come."

The project was first announced in 2019.

The bridge-tunnel is the longest of its kind in Canada and connects the Mercier-Hochelaga-Maisonneuve borough in Montreal with Longueuil on the South Shore, running under and over the St. Lawrence River.

The rehabilitation project will upgrade the tunnel's operating systems, including lighting, electrical and fire prevention.

Highway 25 between Charron Island and the Sherbrooke interchange will also be revamped, and public transit infrastructure will be constructed along Highways 20 and 25.

All in, the total cost will be around $1 billion, and Quebec, the City of Montreal and the City of Boucherville will help foot the bill along with Ottawa.

The tunnel was built in 1967 and is used by around 120,000 vehicles per day, the government noted.