Meet Mr. Fib and Little Miss Surprise, the Newest Characters to Join Beloved 'Mr. Men' Children's Book Series

The duo gets up to silly antics in their new books, which are set to release Sept. 12

<p>Farshore (2)</p> The book covers for

Farshore (2)

The book covers for 'Mr. Fib' and 'Little Miss Surprise'

The world of Mr. Men and Little Misses is expanding! The latest additions? Mr. Fib and Little Miss Surprise.

The new duo are not only joining the beloved children’s book series — which also includes characters like Mr. Mischief, Mr. Calm and Little Miss Brave — but each will also receive a book of their own this fall.

Penned and illustrated by Adam Hargreaves — the son of the series’ original creator Roger Hargreaves, who died in 1988 — the books are slated to hit shelves Sept. 12, and available for pre-order on Amazon now.

Related: PEOPLE’s Picks for the Best LGBTQ+ Kids Books for Pride Month

<p> Ian West/PA Images/Getty</p> Author Adam Hargreaves

Ian West/PA Images/Getty

Author Adam Hargreaves

Recommended for kids ages 2 and up, Mr. Fib will follow the titular character — a cheeky, top hat-wearing green circle — as he, well, fibs. An official synopsis reads, “Mr Fib is the smartest, strongest and funniest Mr Men of all. Well, so he says, but don't believe everything you hear!”

“Mr Fib fibs to impress people, but his fibs are getting bigger and bigger, and one day he goes too far and his friends are upset,” the synopsis continues. “Can Mr Fib learn to tell the truth?”

Related: Chris Pine to Publish Debut Children's Book That He Hopes 'Resonates with the Child in All of Us' (Exclusive)

Little Miss Surprise, meanwhile, promises to follow the newest Little Miss, a purple character with pink hair full of flowers and doodads, as she navigates her penchant for — as her name suggests — surprising people.

“Meet the newest Little Miss who loves nothing better than surprises!” an official synopsis reads. “Little Miss Surprise never knows from day to day what she’s going to do and [who] she’ll do it with”

Throughout its 32 pages, Little Miss Surprise will also interact with another beloved character: Mr. Quiet. “Life certainly isn't predicable when Little Miss Surprise is around!” the synopsis says. “But is Mr Quiet ready for one of her surprising days out?”

<p>Rosemary Matthews/Keystone/Hulton Archive/Getty</p> Mr. Men creator, author and illustrator Roger Hargreaves

Rosemary Matthews/Keystone/Hulton Archive/Getty

Mr. Men creator, author and illustrator Roger Hargreaves

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from juicy celebrity news to compelling human interest stories.

The world of Mr. Men and Little Misses began 50 years ago when its late creator, Roger, published its very first entry: Mr. Tickle.

Roger’s son, Adam, has continued to expand the beloved book series since his father’s death. Speaking about its latest additions, the author revealed that “Mr Fib has been rattling around in my imagination for a long while,” per The Guardian.

Little Miss Surprise, on the other hand, "popped into my head right out of the blue," the author added.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.