Washington ? Actor Tom Cavanagh’s newest gig is taking him behind the scenes at the Smithsonian’s museums.

Best known as the star of television’s “Ed,” Cavanagh will host a series of 30-minute shows for the Smithsonian Institution’s joint TV unit with Showtime Networks Inc., slated to launch in April.

The new company, Smithsonian Networks LLC, is set to announce today about a half-dozen of its initial 60 programs, including a co-production deal with the BBC’s flagship “Timewatch” history series and documentaries focusing on the Smithsonian’s treasured artifacts.

David Royle, executive vice president for programming and production at Smithsonian Networks, said the goal is to do more than “merely museum television” with programs that are “entertaining, informative and fun.”

No carriers have signed on, but negotiations are under way, Royle said.

Cavanagh will host the six-part series “Stories from the Vaults” from the back rooms of the world’s largest museum and research complex, which houses millions of items from art, history, technology and science.

“One minute (Cavanagh) is coming across Phyllis Diller’s joke file, which has every joke that she’s ever told in it, and the next minute he’s taking part in a CAT scan of a Stradivarius, and then he’s in the cold tissue storage center, where they’re keeping everything from beetles to elephant blood,” Royle said.

Smithsonian Networks, which was announced last March, plans to spend at least $10 million for more than 130 hours of programming each year. Museum representatives will check the programs for accuracy and to ensure they align with Smithsonian standards.

“It’s also a good way for the public to learn a bit about the face of the museum,” said aeronautics curator Peter Jakab, who is on a committee reviewing films for the project. “They see our exhibitions, they see our objects, but they’re not necessarily clued in to all the research that goes on here.”

The Smithsonian’s semi-exclusive deal with Showtime has raised concerns among broadcasters, filmmakers and historians whose access to museum archives and experts could be affected.