Lance Makes It 4 with New Son

Lance Armstrong introduced his new son to the world late Thursday night, but not just any old way. He Tweeted it.

Anna Hansen, who Armstrong began dating last summer, gave birth to a 7-pound, 5-ounce, and 20- inch long baby boy named Max shortly before midnight.

"Wassup, world? My name is Max Armstrong and I just arrived. My Mommy is healthy and so am I," the Tweet read.

A later post acknowledged how great the doctor and nurse were during the delivery, and even included a picture of the newborn.

Armstrong had three children with his ex-wife, Kristin, using in-vitro fertilization due to his bout with testicular cancer. They used sperm he banked before beginning chemotherapy treatment.

Following the December announcement by Armstrong and Hansen that they were expecting a baby in June, a spokesperson for the Lance Armstrong Foundation confirmed that the baby was conceived naturally. Armstrong and Hansen reside in Aspen, Colo.

In 2006, Armstrong and singer Sheryl Crow ended their engagement because she wanted kids and he didn't, having just come off of a marriage and having kids.

The seven-time Tour de France winner returned to competition in the Giro d'Italia this May, finishing twelfth overall. Last September, Armstrong announced that he would return to compete in the Tour de France, which begins July 4.