Lock up the kitchen knives and break out the peanut butter. CBS has announced it's going ahead with a fourth season of ''Big Brother,'' Variety reports. Host Julie Chen is expected to return this summer for another go-round with a houseful of exhibitionist, backstabbing shut-ins.
The show, which has grown in popularity over each of the past three summers, has already received 2,000 tapes from would-be contestants, even though formal casting won't begin until March. Returning producers Arnold Shapiro and Allison Grodner tell Variety that there will be only minor tweaks to the format this year. Says Shapiro, ''We will be coming up with new twists and turns in the game to keep it fresh and exciting and unpredictable.''