Are Mariah and Justin Too Big to Sell Stuff on TV?

I see Mariah Carey hawking her wares on HSN. I can see why B- or D-list celebs do that, but a megastar like her?
?Freddie Ball, via Facebook

Mega-star, eh? Sweetie, just...

Danielle Lloyd Karolina Kurkova Rachel Moore Darlene Crawford Kate Moss