Ellen Rubs Ashlee's Baby Bump!

Even though mom- (and bride) to-be Ashlee Simpson has yet to say anything publicly about her impending motherhood, that didn't stop talk show queen Ellen DeGeneres from asking her about the taboo topic when the singer stopped by to tape a performance for Thursday's show.

"I can’t let you sit here and not ask you the question," began Ellen, before daring to ask, "Are you or are you not pregnant?"

In what has become standard avoidance talk for the little sister of Jessica Simpson, Ashlee would only say, "That is definitely something that I choose personally not to discuss except for the fact that maybe… do I look like I had 10 cheeseburgers or something? Because I don’t think I do!" At which point, the young fiancée of Fall Out Boy's Pete Wentz stood up to show off her petite figure.

(photo: Michael Rozman/Warner Bros.)

And while Ellen admitted that Ashlee didn't look obviously pregnant, she did ask the pop star to make her a promise — that she wouldn't wait as long as Jennifer Lopez (who was bursting at the seams, 6-months pregnant with twins) to make the news public.

"I promise you that," laughed Ashlee. "I give you my pinky on that."

And after the two sealed the deal with a pinky swear, Ellen tried one last time: " Is it a boy or a girl?" But to no avail.

Check out the whole hilarious scene yourself on Thursday morning, when Ashlee's visit to The Ellen DeGeneres show airs nationwide.