Johnny Galecki has become a father for the first time

Alongside a photograph of the couple holding their little one's tiny fingers, Johnny captioned it: "With full and grateful hearts we welcome our beautiful Avery into this incredible world. Thank you for all of your love and support. (sic)"

The 44-year-old actor and his partner revealed back in May that they were expecting a baby boy after finding out the sex at their gender reveal party.

Despite being over the moon at the fact he had a son on the way, Johnny previously said he was secretly hoping that Alaina was carrying a daughter for him.

Asked if he had painted his nails bright pink as a hint he knows Alaina is carrying a girl, he said: "I get a little bored looking exactly the same way for nine and a half months every year playing Leonard.

"So we wrapped and I threw some blue in my hair, then I got superstitious that I was manifesting a boy, when I kind of prefer a girl...Don't play this tape for my child years from now! So, I painted my nails pink to try to even out the energy there."

Johnny and Alaina announced in identical posts shared on Instagram back six months ago that they were expecting a baby together.

They said: "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."