Jeremy Piven's new TV series is set in decorous England, not the hedonistic Hollywood of "Entourage." The time is the early 1900s, when booming London would have struck the very 21st-century Ari Gold as a mind-numbing bust.

And, most notably, "Mr. Selfridge," starring Piven as the real-life American entrepreneur whose mission was to transform and conquer British retailing, is airing not on the frisky, few-holds-barred HBO home of "Entourage," but on restrained PBS.

Don't get the wrong idea, cautions Piven, who earned three Emmys for his portrayal of power player Ari. The eight-part series, which debuted with a two-hour episode Sunday, has its hero's brash, lusty passion - for business and women - at its core.

"Yes, it's a period piece. But the term 'period' has to be used loosely, because it's also funny and it has energy and it moves," Piven said. Lovers of standard British costume dramas ("Downton Abbey" fans, you know who you are) shouldn't be put off, he added.

"This will, I think, satisfy those people who want to see the way it was at the turn of the century ... but then you also get all the energy and the sexiness and the humor," he said.

"Mr. Selfridge," based on the nonfiction book "Shopping, Seduction & Mr. Selfridge" by Lindy Woodhead, details Harry Gordon Selfridge's quest to bring brassy American salesmanship to the hidebound world of British shops with his enduring Selfridges & Co.

The series co-stars Zoe Tapper as Ellen Love, a fictional character drafted as an amalgam of Selfridge's assorted extramarital romances, and Frances O'Connor as his loyal but tested wife, Rose. ("He was an exceptionally active man with the ladies," wryly observed screenwriter Andrew Davies, who adapted Woodhead's book for the series co-produced by PBS' "Masterpiece" and ITV Studios.)

Selfridge, who had honed his retailing strategies and marketing skills at Chicago's famed Marshall Field, built an Oxford Street shopping palace that introduced such concepts as elaborate window displays and cosmetics counters, and services ranging from restaurants to beauty salons to a concierge.

His bravura and extravagance in creating Selfridges was boundless, as was his optimism. Some in the British press sneered: "A crusade has been started to force on London superfluous luxuries such as those overstocked across the Atlantic," warned the British Weekly, according to Woodhead's history.

The contrast between the U.S. and the U.K. was part of the project's draw for him, Piven said.

"Our culture and the American dream is butting heads directly with the British culture and the realistic take they have on life," he said. "They believe it's tough out there - very few make it and you probably won't. We're all, "You can do it! You can do anything!'"

Piven found himself fascinated by Selfridge's history, and added some personal memories. Raised in a Chicago suburb, he was exposed to the retail magic Selfridge developed there.

The "amazing" display windows at Marshall Field were something that "I grew up taking for granted. ... My mom would tell me how she would go there as a child and she was taken care of and made to feel special," a hallmark of Selfridge's approach, he said.

While the words "Ari" and "shark" seem made for each other, Selfridge is portrayed as charming.

"I don't think he can help himself. He loved life and he devoured it, and valued people and relationships ... and he treated everyone equally, from the guy that worked in shipping to his right-hand man," Piven said. "Ari was the antithesis, and ruled with an iron fist and was incredibly reactive."

"And, my God, they're both so fun to play. For very different reasons but equally satisfying," said Piven, who won three Emmy Awards for his "Entourage" character said to be inspired by talent agency executive Ari Emanuel, brother of Chicago Mayor Raum Emanuel.

One of the pleasures of switching from Ari to Harry was leaving modernity behind, Piven said.

"I just came off eight years of playing a character that was continuously distracted by his phone and email and everything else," the actor said. "The great thing of going back in time is that you had none of that to hide behind. You're face to face, and actually speak to people."

He may end up juggling the two different worlds. A film based on the HBO series was green-lighted earlier this year by Warner Bros, while "Mr. Selfridge," based on healthy ratings and good reviews during its just-concluded run on Britain's ITV network, has gotten a second-season order for 2014.

Piven, 47, is eager to continue his English adventure as the retailing legend, but has a confession to make: He's no shopaholic.

"I personally don't have a great deal of endurance for shopping. I think women have that endurance gene: They can go and go and go," he said. "I love to box and can go 12 rounds with very little time in between. ... I may have 25 minutes in me for shopping before I hit the wall."