Jessica Simpson has voluptuous lips. And she’s also pregnant. Is that a coincidence?

The siren is under fire from critics, claiming that her lips were injected with Botox. However, the mother-to-be says that it’s her pregnancy that’s plumping up her lips.

Simpson, who is expecting her first child with NFL player Eric Johnson, tweeted a picture of her lips, saying that baby weight is the key to lip plumpness.

Simpson Tweeted: “Woke up looking like the lip injection fairy visited me in the night! Is this how pregnancy face begins? Yikes! Ah, yes, the notorious 'lip injection fairy.”