Caitlyn Jenner claimed to have 20 grandkids on tonight's I'm A Celebrity - but viewers are insisting the 'maths doesn't add up'.

The reality TV star, 70, opened up about family life in an intimate jungle chat with some of her fellow campmates.

When Kate Garraway questioned how many grandchildren she had, Caitlyn said: "20 in December."

Asked what the grand children called her, Caitlyn said: "They’ve come up with ‘Boom Boom’, it kinda stuck, it was easy for them to say."

But some viewers struggled to work out who all of the grandkis are - with many admitting they could only count 16.

Caitlyn discussed her grandkids in the jungle
Kourtney Kardashian surprised Kris Jenner by bringing all of the Kardashian kids onto the Ellen Show

Taking to Twitter , one baffled viewer said: "Pretty sure Caitlyn don’t have 20 grandkids...? Who do the last 4 belong too"

Another asked: "Caitlyn Jenner saying she’ll have 20 grandchildren by December on but my maths isn’t adding up... Who had the last 4? What’s going on?"

A third said: "Did Caitlyn says she has 20 grandkids?... Name them..."

While a fourth agreed: "Did Caitlin just say 20 grandkids? Someone do the maths for me"

Kourtney Kardashian has three kids, Mason, Penelope and Reign with ex-parnter Scott Disick.

Younger sister Kim Kardashian has just welcome her fourth child, Psalm, with rapper Kanye West .

The power couple have three other children - North, Saint and Chicago.

Khloe Kardashian is mum to True, the daughter of Tristan Thompson, while Rob Kardashian and Blac Chyna have little Dream.

Kim and Kanye are proud parents to their children
Kylie with little Stormi

Kylie Jenner secretly gave birth to daughter Stormi Webster in February 2018, who she has with rapper Travis Scott, but Kendall Jenner has no kids yet.

From Caitlyn's first marriage, Burton "Burt" Jenner has two kids, and daughter Cassandra "Casey" Marino has three.

Brody Jenner doesn't have any yet, but Brandon Jenner has one.

This only adds up to 16, hence the confusion, but Brandon is expecting twins with girlfriend Cayley Stoker.

Caitlyn spoke about family life

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I'm A Celebrity 2019

During the intimate jungle chat down by the creek about her famous family, Caitlyn explained that her kids still call her 'Dad'.

She said: "My kids all call me Dad, Kendall asked me first and I said ‘Dad’, I’m your Dad and I’ll always be your Dad till the day I die.

"But what they’re really good at which shocks me all the time is when they’re talking about me, my Dad she and it’s tough to change the pronoun in the middle of it."

* I'm A Celebrity...Get Me Out Of Here! airs on ITV at 9pm