Taking to her blog, The Raddest mom, 27-year-old Lisa excitedly revealed:
‘Jack and I are super excited to share with you all that we are expecting our second baby!
‘I am in my second trimester, feeling great & trying not to eat everything in sight.
‘We feel so blessed that our family is growing & Pearl will have a little brother or sister to play with. It’s crazy to think that we will soon be a family of four!’
Jack, also 27, retweeted her message and has previously admitted his love for parenthood, confessing:
'I feel so deceitful when I take Pearl to the doctor and she has to have a shot. One minute it’s all smiles then sadness.'
The couple married in Hawaii last October, six months after baby Pearl was born.
Kelly recently spoke out about her brother’s bravery and charity work, after he was diagnosed with multiple sclerosis the same year as his wedding.
'He's amazing. He's unstoppable,' she proudly said.
'It's like it's not even there… He always reminds me that it's not just him that we're fighting this race for. It's the 2.1 million people living with it as well.'