If “Saturday Night Live” has a star right now, it has to be Kristen Wiig, the manic comic actress who has branched out into big-screen comedies, including “Knocked Up,” “Walk Hard,” “Whip it” and “Adventureland.”

Like her “SNL” predecessor Will Ferrell, Wiig’s comic creations walk a fine line between the overtly odd and the spectacularly repressed. Wiig made use of both stereotypes during “SNL”‘s 2008 election lampoons by repeatedly playing the woman known as the crazy McCain-rally lady.

Wiig will host tonight’s Christmas special. Or, more to the point, one of her stock characters will take center stage. “SNL Presents: A Very Gilly Christmas” (7 p.m., NBC) puts special emphasis on Wiig’s turn as an evil and impish schoolgirl with a bow affixed to her round pile of hair and a penchant for saying “sorry” with a vacant, malevolent smile. With her catchphrase and simplistic, lip-biting, eye-rolling behavior, Gilly doesn’t seem so much like an SNL character as a parody of an SNL character. Did “Pat” ever get her/his own holiday special?

We have to assume or at least hope that one-note Gilly won’t dominate the whole two hours. Look for plenty of Christmas clips from SNL’s past and appearances by frequent hosts Steve Martin and Alec Baldwin.

• Speaking of stock characters, “Jeff Dunham’s Very Special Christmas Special” (7 p.m., Comedy Central) features holiday gags from his favorite “dummies” Walter, Achmed, Bubba and Peanut, as well as a glance back at some favorite bits from his very popular “Jeff Dunham Show.”

• Grief meets greed and a lifetime of mixed emotions on “The Will: Family Secrets Revealed” (8 p.m., Investigation Discovery), a documentary look at families torn apart by the ambiguous wording of the deceased’s last will and testament, and the confusion that ensues when people die with no will at all.

• “Truth About Online Anorexia” (7 p.m., BBC America) examines peculiar and popular Web sites that extoll the beauties and virtues of self-starvation. Not for the squeamish.

• “Naked Science: Ancient Astronomers” (9 p.m., National Geographic) looks at the cave paintings of Lascaux, France, thought to be some of the earliest examples of man’s artistic expression. While long considered representation of hunter-gathering rituals, some now contend their inspiration may have been the heavens and that these creatures reflect early efforts to map the constellations.

Tonight’s other highlights

• Robert Wagner and Jill St. John host “The World Magic Awards” (7 p.m., MyNetwork).

• An embittered veteran (Clint Eastwood) comes to an unlikely accommodation with his immigrant neighbors in the 2008 drama “Gran Torino” (7 p.m., Cinemax).

• A shooter at a gun store may have had a curious motivation on “CSI” (8 p.m., CBS).

• Olivia returns to our reality on “Fringe” (8 p.m., Fox), guest starring Leonard Nimoy.

• A blow from an errant baseball shifts Jane into flashback mode on “The Mentalist” (9 p.m., CBS).

Cult choice

A magazine columnist (Barbara Stanwyck) passes herself off as a domestic diva until she’s forced to put on an elaborate holiday feast in the 1945 comedy “Christmas in Connecticut” (7 p.m., TCM), made decades before the advent of Martha Stewart or Rachael Ray.