“So lovely to be sharing this pregnancy with my sister @katetwigley who is pregnant with her first bubba.” wrote the Postcards presenter.
33-year-old Rebecca is already the mother of two children Oscar, 4 and Billie, 2 with former AFL player Chris Judd.
The rambunctious pair are often captured spending quality time with their ‘Aunty Kate’ on social media.
31-year-old Kate married husband Matt Seal in a lavish ceremony in 2014, where Oscar was a pageboy and Billie who was then only 8 months old played a special role in the ceremony as a flower girl.
Rebecca has previously spoken of her surprise and delight to learn that she was expecting twins, joking that she could ‘fill a forward line’.
The sisters are due to give birth 10 weeks apart. At 24 weeks pregnant now, Kate will be preparing to enter her third trimester as winter hits, whilst Bec will have to wait until spring to meet her babies.