CBS renews 'Big Brother'

12th edition will air next summer

No surprise here: CBS has ordered a 12th edition of "Big Brother" for next summer.

The three-times-a-week reality series debuted sluggish, then kept growing each week to challenge top-rated rivals like NBC's "America's Got Talent."

"Brother" is one of only a handful of summer reality shows to grow this year, up 7% in viewers and 4% in the adult demo.

The current season airs its two-hour finale next Tuesday.