Responding to the claim, Jeffreys tweeted: "Nope, not pregnant."
"The only one fuelling that rumour would be you, @DailyMailAU . But thanks for the subtle reminder to wear spanx on all casual outings."
One fan asked, "If you gently touch your tummy, what are we to expect?"
Showcasing her wit, she replied: "That I was feeling very satisfied with my breakfast."
Jeffreys married her 37-year-old journalist beau back in April 2017.
The couple met on the set of Nine's Weekend TODAY back in December 2013.
They wed in an intimate ceremony in New South Wales' Kangaroo Valley, at the Ooralba Estate.