Betty White Betty White

Keep your eyes peeled and don't take an ill-timed pee break during Thursday's 30 Rock because you may miss Betty White's guest spot. Well, it's more like a cameo.

"That's such a quick thing. It'll be over before you know it. Don't blink! It's one line. It's a line-and-a-half maybe," she tells TVGuide.com. "I think I'm yelling at poor [Tracy] Morgan."

30 Rock: Betty White guest-stars; is Timberlake next?

Betty White to receive SAG Life Achievement Award