Johnny Galecki, best known for playing the scientist Leonard Hofstader, revealed the exciting news that he is expecting his first child with girlfriend, Alaina.
The 43-year-old announced the news via Instagram, sharing two photos of him and 21-year-old girlfriend Alaina to his 2.8m followers.
He captioned the photo: ‘We are absolutely over the moon to announce that we will soon be welcoming a little one into this crazy and wonderful world.
‘We ask that you please respect our privacy during this celebratory time for us and our families. There truly is love out there for all. We hope ours is the ember of yours, as we feel yours is the ember of ours.’
Alaina soon responded to Johnny’s heartfelt post: ‘I am so excited for this journey with you babe. You’re going to be the best father 💗.’
Alaina also announced the news sharing an intimate selfie of herself and Johnny on her Instagram.
She posted alongside the photo: ‘So happy to announce that we are having a baby!
‘There couldn’t be a better blessing in the world for us and we are over the moon happy.
‘We appreciate as much privacy in this time as we are celebrating with close friends and family, and we are happy to share the news with you.’
Fans and friends were quick to congratulate the expectant parents.
British actress Anna Friel said: ‘Ohhhhh Johnny, that’s what you always wished for. So happy for you . Gracie and me send our massive love to you. How exciting and joyful. ❤️’
Singer Jack Garrat said: ‘Congrats man ❤️❤️❤️.’
The lovebirds only went public with their relationship on social media in September, and in November made their first appearance on the red carpet together at the E! People’s Choice Awards.
And, in December fans were convinced the pair had tied the knot after wearing matching rings.
But, this wasn’t the case as Alaina quickly clarified with the hash tag #notmarried in an Instagram caption.
While Johnny’s appearance in the comedy show is coming to an end – as the Big Bang Theory finale is set to air in just a couple of weeks – his life as a new dad is just about to start.
Johnny previously was in a relationship with fellow Big Bang Theory star Kaley Cuoco for two years – while also playing each other’s love interests in the show.