As Brandon Walsh on the hit TV show, "Beverly Hills 90210," actor Jason Priestly never shied away from making his voice heard among a tight-knit group of friends struggling to find their way through the tumultuous 1990s.

Now, the Canadian actor is lending his real-life voice to a real-life issue: the future of oil and gas development in Canada's Gulf of St. Lawrence.

Environmentalists have enlisted him in a campaign to halt oil exploration and drilling in the gulf, a semi-enclosed inland sea bordered by Canada's five Atlantic provinces, estimated to contain as much as 2 billion barrels of oil in a location that straddles the undersea border between Newfoundland and Quebec.

The Gulf is home to more than 2,000 marine species, including the endangered blue whale and imperiled cod stocks. It's also a lifeline for Atlantic Canada's fishing and tourism industries, drawing fears that oil exploration could bring about a fate similar to the BP oil spill in the Gulf of Mexico.

"As a Canadian and someone who enjoys nature, I am very concerned about the impacts of offshore oil and gas exploration," Priestly says in a video posted on the websites of the David Suzuki Foundation and Sierra Club Atlantic.

"Should this resource be exploited, any oil and gas spill would contaminate the coastlines of all five provinces on the gulf. This is why we are calling for a moratorium on exploring and drilling for oil in the Gulf of St. Lawrence.”

The endorsement from Priestly, who currently stars in the HBO Canada series, "Call Me Fitz," places him in the ranks of a coalition of environmentalists, concerned citizens, fisherman and First Nations groups who support a moratorium on exploration and drilling in the gulf.

Seismic testing  began this fall on a location known as the Old Harry prospect in the waters of Newfoundland, and the Quebec government said it hopes to have a deal hammered out soon with the federal government for exploration in its waters.