Jackson Rathbone walked hand in hand with his girlfriend, Sheila Hafsadi in West Hollywood, California on November 21, 2011. Credit: Fame Pictures

Jackson Rathbone is a true "Bone Daddy" now!

The Twilight actor welcomed his first child, a baby boy named Monroe Jackson Rathbone VI, with girlfriend Sheila Hafsadi on Thursday, his rep confirmed to Us Weekly.

After the birth announcement, Rathbone (full name: Monroe Jackson Rathbone V) took to his Twitter account to thank fans for their well wishes. "Thank you all for the love and support!" he wrote Thursday. "Sheila and I couldn't be happier to have such a beautiful, healthy baby boy, Monroe Jackson Rathbone VI." 

He later added, "Feeling so blessed! What an amazing day! Love and respect, Bone Daddy."

But the celebration was only beginning. He then shared a photo of his father smoking a cigar in honor of the birth of his grandson. "The original (well, the fourth . . .) Bone Daddy!" Rathbone wrote. "Monroe Jackson Rathbone IV celebrating the birth of MJR VI."

And the 27-year-old new dad also decided to join in on the fun a smoked a cigar as well. "Taking a cue from MJR IV . . . What a glorious day!" he tweeted with a photo of himself. "Love and respect, Bone Daddy."

After the actor announced he and Hafsadi, a burlesque dancer, were expecting their first child together in February, Rathbone told Us he was going to his father for parenting advice.

"I have one of the greatest dads in the world," he gushed. "He's just been giving me amazing advice."