'Twilight' Star Jackson Rathbone Welcomes Son

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Jackson Rathbone is a new dad!

The 27-year-old actor/musician, best known for his role as Jasper Cullen in The Twilight Saga, became a first-time parent with girlfriend Sheila Hafsadi on Thursday morning, reports Us Weekly.

The bouncing baby boy, named Monroe Jackson Rathbone VI, weighed in at 8 pounds, 11 ounces.

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"Thank you ALL for the love & support!" wrote Rathbone to his Twitter account Thursday night. "Sheila & I couldn't be happier to have such a beautiful, healthy baby boy, Monroe Jackson Rathbone VI."

The birth comes nearly five months after the couple announced their pregnancy in February, telling the magazine they were "thrilled and excited to be expecting their first child."

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Hafsadi, a burlesque dancer, reportedly met Rathbone during a tour stop with his band 100 Monkeys.