DOCTOR WHO. 9 p.m. Saturday, BBC America.

THE BRITISH could teach American TV viewers a lot about letting go.

As we mount save-our-show campaigns for series that may already have run for five times as many episodes as the original version of "The Office," they've become accustomed to shows that last a six-episode "series" or two before crossing the Atlantic to live for decades more in reruns as "Britcoms."

Maybe they learned to say goodbye from "Doctor Who."

The longest-running science-fiction show in the universe, it's a series that's been reinventing itself every few years - with a long gap or two - since 1963, as one actor after another took on the role of the character known only as "The Doctor."

Generations of Britons have grown up on the show, including the 10th Doctor, David Tennant, who bowed out in an episode that aired on BBC America on New Year's Day, and Russell T Davies, the writer who revived the series in 2005.

They say your first Doctor is the one who sticks with you, but having come in with Christopher Eccleston, only to be startled, then charmed by his transformation after one season into Tennant, I'm not sure I'd agree.

I've adored Tennant and had been dreading the arrival of the 11th doctor, Matt Smith.

Until I saw him in action.

Smith makes his U.S. debut this weekend in an episode aptly titled "The Eleventh Hour," and he, too, is an energetic charmer.

In the world of "Who," of course, it's just about always the 11th hour, The Doctor having saved the world from destruction many times more than "24's" Jack Bauer. (And with, perhaps, fewer violations of the Geneva Convention.)

With producer Steven Moffat stepping in for Davies, whose departure coincided with Tennant's, there may be a shift in tone. It's not just that Smith's a bit younger than his predecessor, but that the show itself suddenly seems younger, too. Davies' darker dreams weren't always confined to the "Who" spin-off "Torchwood," and though Moffat's written some scary stuff for The Doctor before this, Saturday's season premiere feels like a fresh start.

Which could be just what The Doctor ordered.

'Small Island' on PBS

Andrea Levy's "Small Island" gets the "Masterpiece" treatment in a two-parter that begins Sunday (9 p.m., Channel 12).

Two young women, Hortense in Jamaica (Naomie Harris) and Queenie in London (Ruth Wilson) contract marriages of convenience to well-meaning men (David Oyelowo and Benedict Cumberbatch) that will bring two couples together in a particularly intimate way in a post-World War II Britain grappling with issues of race and class.

It's a good and heartfelt story, but I could have done without the sometimes-intrusive narration. Not only does it do little to clarify a narrative that crosses back and forth in time, but it's almost an insult to the actors, who have no trouble getting across the emotions Paula Milne and Sarah Williams' adaptation insists on describing, anyway.

HBO re-ups with 'Treme'

Though I've heard from people who are taking a wait-and-see attitude on HBO's New Orleans series "Treme," the network's jumped in with both feet, this week announcing it's already renewed the show for a second season.

Auditing 'Masterclass'

"I felt like I was on a date, a very, very nervous date . . . where I kept fumbling and then spilled something [and] I tried to make conversation but knew that they're so beautiful and so pretty that I would never have a chance to go on a second date with them."

That's a student talking about spending time with playwright Edward Albee in "Masterclass," a nine-episode series that begins on HBO at 5:30 p.m. Sunday with tenor Placido Domingo mentoring four aspiring opera singers.

Based on a program called YoungArts that brings high school arts students together with some of the icons in their chosen fields, "Masterclass" extends that privilege to its audience, which gets to listen in on the musings of Domingo, actress Liv Ullman (5 p.m. April 25), Albee (5:30 p.m. May 2), dancer Jacques d'Amboise (5:45 p.m. May 9), visual artist Olafur Eliasson (3:45 p.m., May 16), architect Frank Gehry (7 p.m. June 9), choreographer Bill T. Jones (6:30 p.m., June 13), conductor Michael Tilson Thomas (7 p.m. June 18), and artist and filmmaker Julian Schnabel (6:30 p.m. June 27).

Four of the students featured in the series have local ties: Michael O'Brien, now a student at Temple, was part of the Albee workshop, set to air May 2; Cheryl Smith, now a student at the University of Pennsylvania, met with Schnabel; Becky Anderson, now at the Curtis Institute of Music, was mentored by Thomas; and Gabrielle Vitollo, who grew up in West Chester, appears with Eliasson. *

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