Big Bang Theory star Johnny Galecki and his girlfriend Alaina Meyer recently threw a gender reveal party of their first baby. With blue colour splashed all over the place, the couple announced that they are going to have a boy.

Along with their friends, the parents-to-be were dressed in black and white and had a colour spray session of blue. It may not be what he "preferred" as he has discussed on "The Talk" earlier this month. Johnny 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 kinda even out the energy there."

Galecki and Meyer are going to have a son! Galecki, 44, and Meyer, 22, went public with their relationship last September, posting cozy photos of themselves together on their social media accounts. The happy couple made their relationship red-carpet official at the People's Choice Awards in November and announced the pregnancy on May 3 on social media: “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.” Pictures all over social media are proof that the paint party was messy and oh-so-fun!

After the 12-year run of Big Bang Theory came to an end on May 16, a new chapter began for Johnny. Coincidently or not, at the end of The Big Bang Theory, Johnny's character Leonard Hofstadter, who always wanted to have kids finds out that his on-screen wife, Kaley Christine Cuoco aka Penny, is pregnant. While working on The Big Bang Theory, Galecki dated co-star Kaley Cuoco for about two years until December, 2009. They have continued on good terms since their break-up. Kaley went on to wed pro tennis player Ryan Sweeting in December, 2013, and following the end of her marriage to him, went on to tie the knot for a second time with Karl Cook.

Johnny Galecki
"Big Bang Theory" star Johnny Galecki shared his New Year's Eve kiss on Instagram. Pictured: Johnny Galecki at the 25th Annual GLAAD Media Awards on April 12, 2014 in Los Angeles. Getty