The seven-time Tour de France champion announced on his Twitter account Thursday that he and girlfriend Anna Hansen are expecting their second child together.
Armstong tweeted, "Getting ?'s today about someone I'm following, a certain @Cincoarmstrong. What to say? Yet another blessing in our lives. I cannot wait!"
The @Cincoarmstrong account has also been posting messages. The first, written April 20, says, "I got 2 arms, 2 legs, a nickname, and [I'm] 2 inches long. See y'all in October."
Another tweet, posted five days later, says, "I'm now the size of a lemon, 3.5 inches long, and weigh 1.5 ounces. And oh yeah, I'm on Twitter."
The Twitter account lists its name as "JackOlivia Armstrong."
Armstrong also confirmed the baby news to the Austin American Statesman.
He and Hansen welcomed son Maxwell Edward on June 4, 2009. Armstrong also has twins Isabella and Grace, 8, and son Luke, 11, with his ex-wife, Kristen.