The veteran broadcast journalist, 54, said the child was born via surrogate and is named Sebastian.
He added that he is raising the baby with his "best friend and former partner" Benjamin Maisani, who is also in the process of adopting Anderson's 22-month-old son, Wyatt.
"These are the pictures I showed of Wyatt [in 2020,] taken just days after he was born. This is Wyatt today," Anderson said showing off his family photos.
"He is nearly 22 months old. He is sweet, funny, and the greatest joy of my life. If he looks particularly happy in this picture, it's because he now has a baby brother. His name is Sebastian, and I would like you to meet him."
Cooper said Wyatt calls him "Daddy" and Maisani "Papa."
"We're a family," Cooper said.
He announced in January that he would begin hosting in the spring a new show for CNN+ called "Parental Guidance."
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He described it at the time as a "dive deep on all things parenting."
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