The mum-to-be wore a grey and yellow dress and pink sandals while Pearl sported a cute black and pink outfit and a bow in her hair.
The 27-year-old, who is married to Jack Osbourne, announced the news of her second pregnancy on Monday by posting a message on her personal blog, The Raddest Mom.
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"Jack and I are super excited to share with you all that we are expecting our second baby," wrote Lisa underneath a picture of herself with Jack and Peal. "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," added Lisa. "It's crazy to think we will soon be a family of four!"
The former model signed her post "Jack, Lisa, Pearl & Baby No. 2."
Jack and Lisa welcomed Pearl Clementine Osbourne on 24 April 2012 and introduced her to the world two weeks later in an exclusive photoshoot with HELLO! Magazine.
In October the couple married in a romantic Hawaiian ceremony when Pearl was six months old.
Despite the family's exciting pregnancy news, as well as the recent announcement that Kelly Osbourne is engaged to Matthew Mosshart, Jack has spent the past year coping with Multiple Sclerosis.
Just three weeks after Pearl was born Jack, now 27, was diagnosed with the incurable autoimmune disease following a frightening episode during which he lost most of the vision in his right eye.
Since his diagnosis Jack has tried to maintain a positive outlook and is focussing on raising awareness about the disease.
Last week Kelly, 28, praised her younger brother for his ability to cope with the illness.
"He's amazing. He's unstoppable," she told People. "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."