Betty White on Robert Pattinson's sexy praise: 'Now that's a comedy line'

When the world's hottest actor -- Robert Pattinson -- calls you "one of the sexiest women in America" -- what can you say?

Pattinson, 23, raved about Betty White, 88, on "The Today Show" this week: "She's vibrant; it's sexy. I think the more age, the better."

Her response?