Marla Frazee did not immediately start planning what she’d wear to the premiere when Dreamworks Animation optioned the rights to her 2010 picture book, The Boss Baby (S&S/Beach Lane). “This was a 32-page picture book that they were going to have to blow up into a feature-length film,” Frazee said. “I was fascinated by the idea but I was definitely not confident it was going to happen.”

Nor did she make any plans to write a sequel. “A sequel was not on my mind, not even after [The Boss Baby] was optioned, because I have so many friends whose books have been optioned and it’s so rare that it actually ends up becoming a film,” said Frazee.

So much for conventional thinking. The Boss Baby, starring Alec Baldwin as the baby (!!!) and Jimmy Kimmel and Lisa Kudrow as his parents, arrives in theaters on March 31, 2017. Frazee’s picture book sequel, The Bossier Baby (S&S/Beach Lane), debuts next Tuesday. She wrote the story in one day, while on vacation.

“I got a text from my agent, Steven Malk, which said, ‘Alex [Malk’s wife] thinks you should do a sequel to The Boss Baby with a little girl,” Frazee recalled. [At the time, the Malks’ daughter was not quite two.] “I dismissed it right away because people are always suggesting sequels. Kids want sequels. The neighbors ask for sequels. But I never create books thinking about sequels.”

With Malk’s text fresh in her mind, she went for her daily walk on the beach. “Because I was away, I didn’t have the original Boss Baby to look at, but a first line popped into my head so I grabbed my phone and started writing and by the end of the day I sent what I had to both Allyn [Johnston, Frazee’s longtime editor] and Steve, and they both said, ‘You have a manuscript here! Let’s do it!’ ”

Surprisingly, the inspiration for the original boss baby was a baby... cat. “When my youngest son was 15, he wanted a cat for Christmas and we had never had a cat before,” Frazee said. “For two weeks, this kitten was just crazy, pooping everywhere, and driving us nuts. Finally, James said, ‘I’m so sorry I wanted a kitten. It’s stressing everybody out.’ ” There might have even been tears until Frazee reassured him. “I told him, ‘This is nothing,’ but I realized he felt exactly the way I felt when I had a new baby. This little creature was the boss of everybody.”

The baby Frazee created looked like a CEO, dressed in a black suit and tie (with a dropseat for diaper changes, of course), wielding a briefcase full of papers and a demanding attitude. The household esthetic is mid-century modern. “I was harkening back to the black-and-white TV shows I grew up with, like The Dick Van Dyke Show, with the stereotypical white male boss.”

The Bossier Baby needed a different look, though. “I thought she should have an update, come in sleeker, less bogged down with stuff,” Frazee said. “So she has an Etch-a-Sketch she uses as her tablet and she can get rid of all the paper.”

The attitude is pretty much the same, of course: pay attention to ME.

Though Frazee’s artwork has won wide acclaim – she has won two Caldecott Honors and won the Boston Globe-Horn Book Award for The Farmer and the ClownThe Boss Baby is her first work optioned for film. “I’m a huge fan of animation,” Frazee said. “My first job out of art school was in the Disney story department, although it didn’t last because I didn’t have any training in animation. I lasted six weeks.”

It continues to inspire her, however. “I include some kind of sequential motion in most of the books I do, like in the Santa Claus book, [Santa Claus: The World’s No. 1 Toy Expert] where I have a whole double spread of Santa trying out a pogo stick.”

Though she doesn’t have any official role in the making of the film, Frazee says the production team at Dreamworks has been “so generous in looping me in. They’ve opened their doors to me so I can peek at what they’re doing and I’ve met so many people who are so passionate about the project.” She got to see an early version of the film in order to prepare for writing an afterword to The Art of the Boss Baby (Insight Editions, Feb.), an illustrated book about the design and making of the film. Naturally, the story line has been expanded greatly from her original text. See the trailer here.

“Where my book and their story intersect is interesting to me. There’s a definite affinity between my baby and the character in the film,” Frazee says. “But what’s most impressive is how much effort goes into something like this. It’s just an astounding amount of creativity and passion and energy.”

The Bossier Baby by Marla Frazee. S&S/Beach Lane, $17.99 Nov. 1 ISBN 978-1-4814-7162-6