(Cover) - EN Showbiz - Mariska Hargitay is "thrilled and amazed" with her new family addition.

The actress and husband Peter Hermann have adopted a second baby, just six months after welcoming a girl named Amaya Josephine into their family.

The couple - who also have five-year-old biological son August together - brought home Andrew Nicolas Hargitay Hermann, who was born over the summer.

The pair have welcomed their baby son with open arms.

"Their hearts were so opened by the [first] adoption, so they couldn't imagine not taking the opportunity to bring another baby into the family," a source told US Weekly.

"Mariska is thrilled and amazed with all the new blessings and great fortune. She has more love than she imagined!"

Mariska and Peter are enjoying their extended brood. The 47-year-old star hasn't found it all plain-sailing however.

"They are very tired and overwhelmed with the change," the source admitted. "But overjoyed."

Mariska and Peter, 44, married in 2004 after meeting on the set of Law & Order: SVU. (C) Cover Media