'How I Met Your Mother's' Alyson Hannigan: Stacy Keibler's definitely hotter than Lily

alyson-hannigan-himym-320.jpgWhile Robin (Cobie Smulders) is spending her time trying to convince everyone she's hotter than Stacy Keibler during Monday's 100th episode of "How I Met Your Mother", Alyson Hannigan says Lily is doing just the opposite.

Lily's obsessed with getting Marshall to admit that Keibler's character is sexier than she is.

"He's being very gentlemanly and it's pissing her off," says Alyson in the clip below.

I say, to each their own. I get where Marshall's coming from.

But perhaps we should let "Project Runway"'s Tim Gunn -- who is also guesting in this week's episode -- settle the debate.

Seems Alyson, who wants Gunn to move in with her, already has an idea of what he'd say...

"How I Met Your Mother"s' 100th episode airs Monday (Jan. 11) at 8 p.m. on CBS.

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Photo credit: CBS