For 20 years the I’m A Celebrity contestants’ outfits have varied in style from skimpy colourful tank tops to khaki shirts – but one crucial element has remained the same.

Despite all the wardrobe changes, the celebrity’s voting number is a staple and has always been printed on their T-shirt because, most importantly, it’s what helps them stay in the compeтιтion.

Viewers are used to calling up the same landline number but changing the last two digits depending on which celebrity they wish to vote for.

So when eagle-eyed fans spotted they were missing on Sunday night’s show, social media was filled with questions demanding to know where they had gone.

MailOnline can reveal that this is because less people are voting by phone, choosing to vote via the app instead.

A show source told MailOnline: ‘Over the years the number of people voting by phone has declined and it’s become a very small proportion of votes cast.’

The stars of this year’s I’m A Celebrity are wearing T-shirts without their voting number on them

The backs of their T-shirts are only emblazoned with their names

MailOnline can reveal that this is because less people are voting by phone, choosing to vote via the app instead 

The insider went on: ‘To simplify the message to our viewers, we have chosen to only have free online voting this year via the app.’

It comes after ITV’s other shows Dancing on Ice and Britain’s Got Talent also ditched the phone voting system – which could upset older viewers who do own a mobile phone.

But on opening night the I’m A Celeb app was plagued by technical issues, leaving viewers unable to vote for the first celebrity to do a bushtucker trial.

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Despite the problems, an overwhelming number of votes came in for the social media star GK Barry, 25, to complete the first solo bushtucker trial, the Vile Volcano.

Hundreds of viewers reported problems that the ITV app would not allow them to register their mobile phone and kept reporting: ‘Something went wrong. Please check your connection, refresh your browser and try again.’

Outraged voters took to X, formerly known as Twitter, to share their annoyance.

One person wrote: ‘“The public have been voting”… no we haven’t, we can’t get on the bleeding app.’

Another added: ‘Great. Now the votes are closed!!! So flipping angry. I’m A Celebrity and ITV sort your voting app out. What a mess.’

Fred Sirieux pictured with his voting number on his T-shirt on I’m A Celeb last year 

Fans shared their confusion at the disappearance of the voting numbers on social media 

Meanwhile, others reported that the app rebooted just as the voting closed last night. 

One person wrote: ‘Great the voting is closed. I’m now getting loads of codes coming through for me to log in. 

‘But I still can’t use any of them to log into the site so I can vote.’

Another added: ‘I literally got four texts in a row with a code as soon as voting closed.’

I’M A CELEBRITY 2024: MEET THE ALL STAR LINE UP

OTI MABUSE  

Oti Mabuse has already two Strictly glitterballs under her belt

AGE: 34

OCCUPATION: Professional dancer

FAMOUS FOR: Oti is best known for being a professional dancer on the British television series Strictly Come Dancing, which she won in 2019 and 2020. 

DANNY JONES 

Danny Jones is one of the bookies’ favourites to win this year’s I’m A Celeb

AGE: 38

OCCUPATION: McFly singer

FAMOUS FOR:  Danny is one of the lead vocalists and the lead guitarist for pop-rock band McFly. 

He is also a coach on The Voice UK. 

BARRY MCGUIGAN 

Former boxer Barry McGuigan is heading into the jungle

AGE: 63

OCCUPATION: Retired professional boxer

FAMOUS FOR:  Barry was nicknamed The Clones Cyclone and held the WBA and lineal featherweight тιтles from 1985 to 1986. 

GK BARRY

GK Barry is a TikTok star who recently joined the ITV family on Loose Women

AGE: 25

OCCUPATION: TikTok star 

FAMOUS FOR: Grace is known for her comedic commentary on culture, lifestyle, and fashion. She has over 3.6 million followers and recently joined the Loose Women panel. 

DEAN MCCULLOUGH 

ITV bosses are hoping Dean McCullough will ruffle feathers in the camp

AGE: 32

OCCUPATION:  Radio 1 DJ 

FAMOUS FOR:  Radio 1 DJ Dean has been signed by I’m A Celeb bosses, in the hope that he will ruffle feathers with his outspoken views. 

Earlier this year it was announced Dean would be taking over the BBC Radio 1 Early Breakfast Show, after previously fronting the afternoon slot.  

JANE MOORE  

Jane is best known as a panellist and anchor of Loose Women

AGE: 62

OCCUPATION: Journalist

 FAMOUS FOR:  Jane is best known as a panellist and anchor of Loose Women between 1999 and 2002. 

She returned as a regular panellist from 2013 onwards.

Jane takes on the challenge following her high-profile split from husband of 20 years, Showbiz agent, Gary Farrow. 

MELVIN ODOOM  

Melvin was previously courted by I’m A Celeb bosses back in 2021

AGE: 44

OCCUPATION: DJ and TV presenter

FAMOUS FOR: His work on radio. Melvin was previously courted by I’m A Celeb bosses back in 2021, but turned down the offer at the last minute.

He also had a primetime stint on Strictly back in 2016.

COLEEN ROONEY 

Reports claim that she has been offered the biggest deal in the show’s history

AGE: 38

OCCUPATION: WAG

FAMOUS FOR: Wagatha Christie case against arch rival Rebekah Vardy.

Reports claim that she has been offered the biggest deal in the show’s history, exceeding Nigel Farage’s £1.5million from last year.

ALAN HALSALL  

Alan Halsall is best known for his role as Tyrone Dobbs on Coronation Street

AGE: 42

OCCUPATION: Actor 

FAMOUS FOR: Coronation Street actor Alan Halsall was forced to withdraw from I’m A Celeb last year, after undergoing ACL Reconstruction surgery.

Bosses have now convinced the actor to sign up again, and no doubt he will draw in a huge fanbase thanks to his long-running role as Tyrone Dobbs on the soap. 

TULISA  

Tulisa is making her career comeback after reuniting with N-Dubz last year

AGE: 36

OCCUPATION: Singer and former X Factor judge 

FAMOUS FOR: Tulisa reunited with N-Dubz last year for a tour after first finding fame with the band in 2007.

In 2011, she became a judge on The X Factor and went on to launch her debut solo album, The Female Boss. 

She released her fourth album with N-Dubz last year.