The 31-year-old model and her husband, former NBA star Marko Jaric, welcomed a second daughter who they have named Sienna and Adriana revealed their two-year-old daughter Valentina is thrilled to become a big sister.
She wrote on twitter: "Marko and I are overjoyed to welcome Sienna into our family and Valentina is looked forward to becoming a big sister."
The Victoria`s Secret beauty - who met Marko in 2006 and married him in February 2009 - has previously proclaimed motherhood to be the "best job in the world".
She has said: "The best job in the world for me is being a mom. I never thought I could love so much. I always thought, does unconditional love exist? Now I know it does because I feel it."
Brazilian Adriana previously admitted she knew she wanted to settle down with Marko and have children when they first met.
She said: "I knew he was the one and I could see myself married to him and with a big family."