Twenty contestants learn who was chosen to return to the house and compete for $500,000 on “Big Brother 7: All Stars” (7 p.m., CBS).

Julie Chen hosts “Big Brother” and maintains her position as anchor of “The Early Show.” There has long been a symbiotic relationship between reality shows and morning “news” programs, where the competition to attract guests and ratings can be intense. “The Early Show” has had the advantage of interviewing exiting “Survivor” stars. “Today” has gotten “Apprentice” winners and losers, and “Good Morning America” has interviewed “Bachelor” contestants over the years.

This has been fine for network promotion, but has it taken a toll on “news”? Morning shows have been combining entertainment and hard news since the inception of “Today” back in the 1950s. And many morning hosts have graduated to more serious fare, including Tom Brokaw, and more recently, Charles Gibson and Katie Couric.

Some wonder openly whether Couric will have the gravitas to pull off a nightly news program. The fact that similar questions have not been raised about Brokaw or Gibson indicates that some of these concerns have as much to do with her gender as her morning-show resume.

But it doesn’t help when her longtime “Today” co-host Matt Lauer “stars” in a grotesque train wreck like his recent “Dateline” interview with singer and troubled mother Britney Spears. It was hard to tell what seemed more ghastly and inappropriate: Spears’ gum chewing or Lauer’s contemptuously casual attire. Spears can show herself off like a prize pig at a 4-H competition, but journalists should wear socks.

Lauer’s bizarre chat with Spears was outdone only by CNN’s Anderson Cooper’s just-between-us-celebrities conversation with Angelina Jolie. But Cooper is no stranger to the odd intersection of television journalism and reality hype. He was, after all, the host of “The Mole II.”

Is it any wonder why more serious journalists have hightailed it for other venues? Ted Koppel will make documentaries for Discovery, and Brokaw is hosting a two-hour special on global warming July 17 on Discovery.

Tonight’s other highlights

¢ Yo-yo artists experience some ups and downs on “Master of Champions” (7 p.m., ABC).

¢ Chris discovers adult magazines on “Everybody Hates Chris” (7 p.m., UPN).

¢ Beauty-pageant dreams on “My Name is Earl” (7 p.m., NBC).

¢ On three episodes of “The Office” (NBC), Dwight’s power trip (7:30 p.m.), conflict resolution (8 p.m.), casino night (8:30 p.m.).

¢ Would-be stars compete to join a prefabricated band on “Rock Star: Supernova” (8 p.m., CBS).

¢ The results are read on “So You Think You Can Dance” (8 p.m., Fox).

¢ On two episodes of “Grey’s Anatomy” (NBC), residents juggle life and work (8 p.m.), Meredith risks it all to save a newborn (9 p.m.).

¢ Evidence vanishes on “CSI” (9 p.m., CBS).

¢ Gunshots ring out on “Windfall” (9 p.m., NBC).