It was reported this week that the Lizzie McGuire star and husband Mike Comrie were expecting their first child together.
However, Duff took to Twitter on Wednesday to shoot down the speculation.
"Wow what a way to wake up and find out your pregs! It’s just a rumour guys! Not true. But thanks for all the good wishes! Lol," she tweeted.
The actress also dismissed the rumour in a text message exchange with Access Hollywood's Billy Bush.
When asked if she was expecting, Duff texted to Bush: "Nope, not pregs! Be nice to know who my ‘friend’ is though that is telling people that."
Her representative also told Gossip Cop: "Hilary is not pregnant."
Earlier this week, Duff revealed that she is excited to have children with Comrie.