Jessica, 32, proudly tweeted a snap of her bare stomach over the weekend, telling followers she is "bumpin' and proud!"
The former Newlyweds star chose Christmas Day to confirm rumours that she and fiancé Eric Johnson are expecting their second child together.
They welcomed daughter Maxwell in May 2012.
Jessica has been enjoying a relaxing Christmas and New Year holiday in Hawaii with Eric, friends and family - treating us to lots of snaps of herself looking radiant in the sunshine. Us, jealous?!
Jessica has been a spokesperson for Weight Watchers for the past year in a rumoured multi-million dollar deal, as she used the programme to help shed her baby weight.
However, it was announced by the company last week that she will suspend her programme during this pregnancy and instead have her weight monitored by a doctor.
> Pregnant Jessica Simpson beams in make-up free photo: picture!
> Check out the cute way Jessica Simpson announced she is pregnant!