How You Know Her: Kreuk is best known for playing Clark Kent's first true love Lana Lang on Smallville. Always one step away from finding out Clark's secret, Lana was the perpetual damsel in distress.The tables have turned and Kreuk is now the one saving herself — and others — portraying an ass-kicking cop who teams up with a semi-beastly vigilante to investigate a shady government agency whom supposedly murdered her mother.

How You Know Her: Liu's breakout TV role was as the cold, ruthless and hypersexual lawyer Ling Woo on the legal dramedy Ally McBeal. She was also one of Charlie's angels in the film franchise. She once again plays a cold problem-solver, this time as the gender-bending Watson, a former surgeon and sober companion to Jonny Lee Miller's Sherlock Holmes, in the updated adaptation of the classic detective tales.

How You Know Her: Sigler played sullen Mafia princess Meadow on The Sopranos for six seasons. Sigler does a complete 180 to play Emily, a happily married stay-at-home mom of two in this Jimmy Fallon-produced sitcom. Unlike Meadow, Emily is optimistic, outgoing and has solid relationships with both her husband and his friends. Why shouldn't she smile?

How You Know Them:Garcia Swisher has played everything from ditsy teen mom to smart nanny, and this time she'll be a woman in charge of her grandmother's practice. Kirk, meanwhile, goes from carefree, irresponsible and incredibly comedic sidekick on Weeds to the exact opposite: the misanthropic lead. Kirk will trade the bong for a stethoscope as the misanthropic lead who loves animals, but hates their owners. Garcia Swisher will ditch the fake pregnancy belly for one of the first times as his bubbly, put-together ex who becomes the manager of his practice.

How You Know Them: On Reba, she played a woman named Reba who finds out her husband is cheating and that her teenage daughter is pregnant. Whether it be on Murphy Brown, The West Wing Desperate Housewives, or in countless films, old pro Tomlin has perfected playing stubborn, opinionated and hilariously outspoken. McEntire again plays a woman named Reba who leaves her cheating husband — but this time she gets to show off her musical chops as an aspiring country singer. Tomlin’s character, Reba's mother, Lillie Mae, has the same sharp tongue, but she’s a little softer around the edges, thanks toa burgeoning medical-marijuana habit.

How You Know Them: Panettiere was the cheerleader everyone had to save on Heroes. Britton played coach's wife Tami Taylor on Friday Night Lights and the doomed Vivien Harmon on last season's "miniseries" American Horror Story. Just like Mrs. Coach, Britten's new character, Rayna James, is easy to root for as a fading country music veteran who is asked to open for Panettiere's pampered country-pop princess Juliette Barnes. (Think Taylor Swift with one hell of a mean streak.)

How You Know Them: Krumholtz spent six years nerding out on CBS' Numb3rs as floppy-haired math genius Charlie Eppes before his very short stint on The Playboy Club last season. Urie brought the snappy one-liners to Ugly Betty as Wilhemia's flamboyant assistant Mark St. James. On Partners, they're BFFs Joe and Louis, the former straight, the latter gay. The sitcom is a departure from the serious material Krumholtz has been doing on the small screen, but you know he's capable of the funny if you've seen the Harold & Kumar movies. Urie? We expect even more sass and spunk.

How You Know Them: O'Quinn is best known as the stoic and mystical crash survivor John Locke on Lost. Williams was nominated for an Emmy as the glamorous but self-centered Wilhelmina Slater on Ugly Betty and most recently played the equally pampered ex-Mrs. Yankee Renee Perry on Desperate Housewives. On 666 Park, O’Quinn takes that air of mysterious authority to play Gavin Doran, the owner of an apartment building where possibly demonic events occur. The role of Gavin’s socialite wife, Olivia, is not much of a change of pace for Williams.

How You Know Him:Last seen saving lives as superhero Oliver Queen (a.k.a. Green Arrow) on Smallville. (Viewers looking to get their Oliver Queen fix can check out Arrow, the CW's Wednesday night take on the comic, with Stephen Amell in the title role.) Hartley is still saving lives, but this time in a much more, shall we say, human role on the CW's medical dramedy. As Emily's med-school crush, Will, the only arrow Hartley will interact with this time around will be Cupid's.

How You Know Him: Could he be any funnier? Perry mastered the sarcastic one-liner as Chandler Bing on Friends, followed by slightly less amusing stints on Studio 60 on the Sunset Strip and Mr. Sunshine. Now, he'll try to put a smile on your face by tackling, of all things, grief. Then again, Chandler did have a pretty sad (read: pathetic) upbringing.

How You Know Him:On Twin Peaks, he played an introspective, Buddhist detective investigating a murder. On Desperate Housewives, he played a devoted but manipulative dentist covering up a murder and on Sex and the City, he played a doctor who just couldn’t get it up. Alrighty then! This time, the chameleon steps into the expensive leather shoes of a powerful law firm partner who’s not afraid to break the rules and think outside the box — or in this case, beyond the big hair.

How You Know Her: She plays Kelly Kapoor, a drama-queen customer service rep on The Office. (Behind the scenes, she also writes and produces the show. Here, Kaling plays a different Mindy (last name Lahiri), a successful OB/GYN whose love life is just as melodramatic as Kelly's. She has an unhealthy obsession with — and belief in &mdassh; the clichés of romantic comedies.

How You Know Him:Gilford first rose to fame as the sweet and sensitive QB1 on Friday Night Lights. He recently played a confident newbie surgeon on the short-lived Off the Map.He'll tug on viewers’ heartstrings once again as a sweet, soft-spoken doctor — and boyfriend to a do-gooder doctor with a big debt to the mob.

How You Know Her: Her three seasons on Real Housewives of Atlanta spent trading insults and coining catchphrases prepared Leakes well for her hilarious (but harsh!) role on Glee as Roz Washington, Sue’s Olympian nemesis. Leakes plays a sassy but lovable assistant to Bryan, one-half of a gay couple using Goldie (Georgia King) as a surrogate. Her many memorable blow-outs with ex-BFF Kim Zolciak will look like child’s play compared to Rocky’s differences with the ignorant Jane (Ellen Barkin), Goldie’s conservative/offensive grandmother.

How You Know Him:Esposito earned an Emmy nomination for his role as the unassuming, but terrifying and ruthless meth kingpin Gus Fring on Breaking Bad. In Revolution, his character Captain Neville is more outwardly hostile and not afraid to make an example of anyone as the ruler of a world devoid of electricity.