Credit: Todd Williamson/

Her baby on The Office is a little girl (named CeCe), but in real life, Jenna Fischer's first child is going to be a boy!

The actress, 37, broke the news during a Tuesday chat with Jay Leno for The Tonight Show. "This is the second grandchild [for my parents]," Fischer said, "but first grandson."

As Leno got excited over her subtle announcement, Fischer added, "This is exclusive, Jay...When I went to my movie premiere the other day a reporter asked me if I knew what I was having, and I said I do, but I'm not sharing that yet because I’m [going to] have Jay be the first to know."

The star, featured in new film A Little Help, first revealed her pregnancy (it will be the first child for Fischer and husband Lee Kirk) in May. When's their son due?

"September we're in what they call the home stretch," Fischer said.