Lithgow has been a busy grandpa, who has released his eighth children's book "I Got Two Dogs," in addition to starring in Arthur Miller's "All My Sons" on Broadway.
"I Got Two Dogs," is based on two dogs named Fanny and Blue, who are rascals that get into mischief. The book is filled with funny rhymes and wonderful pictures.
"It's an illustrator named Robert Newbecker, whom I had not worked with before. One of the nice things about these books is I've worked with five or six different illustrators and they just all are superb," Lithgow told Early Show co-anchor Harry Smith.
According to Lithgow, the text is the lyrics to a sing-along song and a CD is included with the book.
"Out of all the songs that I've made up for kids, this is their absolute favorite," he said.
At this point in the Emmy and Tony Award-winning actor's career, he has accomplished so much, yet he continues to thrive in other areas.
"It's been very organic. It all started with my own little children, and all of their friends, and my oldest is 36 now, so it's a long, long time," he said.
With two grandkids, Lithgow is reliving his own childhood and that of his own children.
Lithgow is taking on Broadway eight times a week with Arthur Miller's "All My Sons" on Broadway, which just opened last week. Lithgow acts alongside Katie Holmes, Dianne Wiest and Patrick Wilson.
"It couldn't be more different. I'm practically schizophrenic these days," Lithgow said.
"It's just extraordinary. It's Miller's first major success. In fact, it was given the very first Tony Award for best play in 1947. It's an extraordinary play, which is having an amazing impact on audiences because it's a 60-year-old play, which is uncannily appropriate to this day and age with issues like war profiteering, war dead, accountability and all of that guilt," he said.
Lithgow plays Joe Keller, which he refers to as "one of our great tragic heroes, along with Willy Loman, Eddie Carbone -- Arthur Miller's other great creations."