Jack Osbourne is expecting his second child.

The former reality TV star - who already has a two-year-old daughter, Pearl, with his wife Lisa Stelly - revealed the pair are set to add to their brood by sharing a photo of his spouse's blossoming baby bump on his Instagram account.

He captioned the image: ''Supprise!!!!! #round2 #babyinbound (sic)''.

Lisa, 27, also broke the news she is over four months pregnant on her lifestyle blog, Raddest Mom, and added that little Pearl couldn't wait to meet her new sibling.

She wrote: ''I'm pregnant! Pearl is very happy to become a big sister. She diligently reads her 'I'm a big sister' books every night & recites to me her plans of bathing, feeding, singing to, and holding the baby.

''We are more than halfway through this thing & are very excited to be parents again! Thanks for all the well wishes :).''

The couple - who married in Hawaii in October 2013 - revealed they were expecting a sibling for Pearl in August 2013 but sadly lost their second child, a baby boy, just a few months later.