Jack Osbourne is going to be a dad, and Ozzy Osbourne a grandpa – again! The happy news comes courtesy of the recently-engaged 25-year-old himself.Congratulations are in order for Jack Osbourne and fiance Lisa Stelly, who are expecting their first child together! News that Jack Osbourne is going to be a first-time dad was revealed by the reality show veteran himself, during an appearance on Piers Morgan Tonight.Jack Osbourne, the 25-year-old son of rocker Ozzy Osbourne, revealed the news to Piers Morgan on Tuesday night. \"I\'m going to be a dad,\" the newly engaged Osbourne shared. \"I\'m excited. I\'m a little nervous.\"Among the first well-wishers congratulating Jack Osbourne on his fiance\'s pregnancy was sister Kelly Osbourne. \"Been waiting 2 say this for so long im the happiest girl in the world im going to be an auntie!\"It appears that mom-to-be Lisa and the aunt-to-be Kelly were busy bonding when Jack Osbourne\'s baby announcement aired. Around the same time as the congratulatory tweet, Jack\'s sister Kelly also shared, \"Girls night in w/ @lisamarstelly my future sister in law & mother of my niece/nephew we are so happy the news is out so i can talk about it.\"Lisa Stelly,  who shared the picture above through her own Twitter account in August, also seems to be feeling the future sister-in-law love. In response to Kelly Osbourne\'s posts on Twitter Lisa tweeted, \"Just spent the last hour on the phone with @MissKellyO ....she will be the best sister-in-law ever!