And their bundles of joy have some very unusual names.
'Miss Araminta Mae and Master Teddy Gene born 22nd February at 7.29am and 7.30am. Our hands and hearts are so full,' wrote the blonde next to a photo of herself cuddling her newborns in a hospital bed.
Jemima and Gene also share two other children together.
Amongst the well-wishers was a message from Phoebe. 'They are perfect in every way. Love you mummy, you inspire me everyday,’ she wrote.