(CNN) -- Seven-times Tour de France winner Lance Armstrong has announced he is now the proud father of a newborn baby son called Max.
Armstrong has become a father for the fourth time following the birth of his son Max.
The 37-year-old survivor of testicular cancer announced the news via his Twitter page, reporting that his new child weighed seven pounds and five ounces and is 20 inches long.
In a posting on his Twitter page, Armstrong displayed a picture with the caption "Wassup, world? My name is Max Armstrong and I just arrived. My Mommy is healthy and so am I!"
Armstrong announced last December that he and girlfriend Anna Hansen -- an actress and one-time beauty queen -- were expecting their first child together. The American has three children with former wife Kristin.
Armstrong returned to competitive cycling this year, following a three-year break, in an attempt to publicize his Livestrong cancer foundation.
He suffered a broken collarbone in a race in Spain in March, but returned for last month's Giro d'Italia, where he put in an impressive overall performance in preparation for his attempt at an eighth Tour de France title next month.
Armstrong regularly communicates with fans and journalists alike by posting messages on the Twitter social networking website.