Ian McKellen, best known to popular audiences for his work in the “X-Men” and “Lord of the Rings” franchises, strides the boards in a three-hour “Great Performances” (7 p.m., PBS, check local listings) presentation of William Shakespeare’s stage tragedy “King Lear.”

Considered one of the great Shakespeare interpreters of his generation, McKellen has played Richard III, Macbeth and Iago in “Othello.” This “Performances” is a televised recreation of the Royal Shakespeare Co. production that toured internationally in 2007.

• I can’t tell whether this year’s crop on “American Idol” (7 p.m., Fox) is more evenly matched or simply less exciting. When Alexis Grace got the boot last week, I was hardly surprised, but not necessarily convinced that she was the bottom of the compost pile. Anoop Desai seems like the nicest guy in the world and everyone’s idea of a swell son-in-law, but I’m not convinced that he’s pop-star material. Megan Joy’s wobbly “Walkin’ After Midnight” got the benefit of the doubt because of her terrible flu, but I really wonder whether she’d still be in the running if she weren’t so pretty. She already looks as if she could be the star of any number of CW teen melodramas.

I’ve come full circle on Adam Lambert. At first, I found him a little too perfectly manicured and tweaked to be real. To quote Randy, I was not “feeling it.” But his audacious country-week performance of “Ring of Fire” earned my respect. It takes a lot of nerve to put a Middle Eastern spin on a country standard, particularly when contemporary country music has become so safe and inoffensive.

Yes, his version of “Ring of Fire” was weird, but it’s a weird song, with lyrics about lust and desire couched in religious imagery. And was Lambert’s decision to evoke the desert sands of Led Zeppelin’s “Kashmir” any quirkier than Johnny Cash’s use of a mariachi band? Lambert’s “Fire” was the first “Idol” performance in a long, long time to make me sit up and think. And the fact that Simon Cowell dismissed it didn’t hurt.

Speaking of Cowell, he appears to have crossed a thin line between critical and merely petulant. In contrast, Paula Abdul seems to have sworn off the crazy talk and often makes good points in a manner that borders on consistent coherence.

Lil Rounds remains the most talented and assured of the bunch. And tonight’s Motown-themed contest should give her a nice platform. Smokey Robinson and Ruben Studdard will perform on tomorrow night’s results show.

Tonight’s other highlights

• Ted brings his daughter to work on “Better off Ted” (7:30 p.m., ABC).

• Murder in the morgue on “Life” (8 p.m., NBC).

• One survivor deviates from the plan on “Lost” (8 p.m., ABC). I knew all of Sawyer’s reading would amount to something.

• A subway slaying doesn’t fit any pattern on “CSI: NY” (9 p.m., CBS).

• A news anchor’s love life inspires murder on “Law & Order” (9 p.m., NBC).

• Sam is suspected by both cops and criminals of being a triggerman on “Life on Mars” (9 p.m., ABC).

• Ellen gets the FBI to change its approach on “Damages” (9 p.m., FX).

Cult choice

Ronald Reagan and future first lady Nancy Davis co-star in the 1957 drama “Hellcats of the Navy” (10:15 p.m., TCM).