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Todd Anthony, BBC Worldwide
Capt. Jack (John Barrowman) and Capt. Hart (James Marsters).

LOS ANGELES — Attention, fans of quick-witted, Brit-flavored science fiction television: Capt. Jack is back.

"He's still the same Jack, but he's a little more lighthearted," says John Barrowman, who plays cheeky charmer Capt. Jack Harkness on "Torchwood," BBC America's flirty, fast-paced series.

"He's resolved a lot of his issues," Barrowman says of his time-traveling, alien-hunting hero who wears World War II-era togs and cannot die. "He's got a new sparkle in his eye."

Introduced in 2005 on the BBC series "Dr. Who," Jack is coy about his shadowy past as a Time Agent — akin to an intergalactic CIA operative — turned fast-talking con artist.

In the second season of "Torchwood," premiering Saturday at 7 and 10, Jack returns to the clandestine Torchwood agency in Cardiff, Wales, where he watches over an alien-spewing rift in space and time beneath the city streets.

Together with his hip, young Torchwood team, Jack battles his old pal, the time-traveling psychopath Capt. John Hart (James Marsters of "Buffy the Vampire Slayer").

As always, Torchwood operates outside the law and the British government. It stands tall against all manner of monsters, including a recurring cast of nasty, sewer-dwelling weevils.

But Jack and crew still find time for office romance and ill-fated, inter-species love affairs — of the same- and opposite-sex sorts.

"Omnisexual is the science-fiction word we like to use," says Barrowman, who sounds very American, both on- and off-camera. Born in Scotland, he grew up in Illinois.

"In the sci-fi setting we can talk about things that you probably couldn't talk about on a regular nighttime drama," the 40-year-old Barrowman says.

"I think audiences just get Jack because he's honest," he says. "To finally see a character who doesn't care who he flirts with, I think is a bit refreshing."

The ace Torchwood team also includes steely Dr. Owen Harper (Burn Gorman), techno-savvy Toshiko Sato (Naoko Mori), office administrator Ianto Jones (Gareth David-Lloyd) and compassionate former cop Gwen Cooper (Eve Myles), who is typically the conscience of the group.

All of Jack's cohorts are just as hormonal as he is.

"Yes, it is a science-fiction soap opera," says Myles, who is Welsh.

To executive producer Julie Gardner, "Torchwood" — an anagram for "Doctor Who" — is "warm science fiction."

"It's the type of science fiction that has a proper kind of human grounding," Gardner says.

That grounding includes turf trod carefully on U.S. television.

"You will see relationships develop between two males," Barrowman says. "You will see them show affection for each other. You will see two women show affection for each other."

Before moving to England in 1989, Barrowman starred on the Fox series "Central Park West" and NBC's "Titans."

In Britain, his career soared with "Dr. Who" and "Torchwood," plus turns in West End musicals. He also is a judge on the musical-theater contest series, "Any Dream Will Do."

"The thing about working in television in the U.K., it's about being me," says Barrowman, who is openly gay and in a longtime partnership with architect Scott Gill.

"I've been pretty much open and out since I started working over here," Barrowman says. "It's a great reflection on the TV industry here."

Barrowman reflects further in his autobiography, "Anything Goes," due for release this month in Britain and later in the U.S.

Meanwhile, "Torchwood" has been a blast for Barrowman and his co-stars.

"It's one of the best playpens ever," Barrowman says. "I get to go to work and play with gadgets and drive really big, fast cars. I get to shoot aliens and fly spaceships.

"And I get to kiss everybody."