By Kate Ward
Updated October 18, 2010 at 08:25 PM EDT

Tour de France champion Lance Armstrong has welcomed a daughter with Anna Hansen, he tweeted Monday. “Olivia Marie Armstrong has arrived!” he wrote on his Twitter page. “Thanks to you all for the support and well wishes. Momma and Olivia (@Cincoarmstrong!) are doing great. She’s a beauty!” The couple has a 16-month-old son, Maxwell Edward. The cyclist also has three children with his ex-wife Kristin Armstrong: 9-year-old twins Isabelle and Grace and 11-year-old Luke.