Channel 5 has been accused of promoting a Nazi sympathiser after it emerged that a contestant on its Celebrity Big Brother show has previously expressed her admiration of Hitler and appeared on her Facebook page posing in front of an image of Auschwitz while wearing a swastika and SS cap.

Anti-semitism campaigners said the comments of Tila Tequila, a Playboy model and singer appearing in the latest iteration of the long-running reality television show, made her a “totally unacceptable participant” in the programme and questioned how her record had been missed by producers.

The entertainer, whose real name is Thien Thanh Thi Nguyen, has strongly denied that she is anti-semitic and in 2012 said she was considering converting to Judaism.

But in a series of online postings, including a blog entitled “Why I sympathise with Hitler Part 1: True History Unveiled”, which has since been removed, Ms Nguyen has described the Nazi leader as a “good man” to whom she felt forgiveness.

Nguyen said Hitler 'stood up for his country in a desperate time' (Getty) (Getty Images)

She wrote: “He was not a bad person as they have painted him out to be. Not even close!!! Here is a man who was not a coward, stood up for his country in a desperate time of need… and yet not only did he try his best to help his country and people get out of what was a time of depression, economic collapse, high unemployment… he lost the war and was painted out to be a monster after his death. This is what breaks my heart.”

She added: “Hitler was a good man and it takes some f***ing balls for someone to say this out loud in this day and age, especially for a public figure like myself.”

The mother-of-one, who was born in Singapore to Vietnamese parents, is one of 13 participants in the 16th series of Celebrity Big Brother, whose producers have attempted to breathe fresh life into ratings for the ageing reality television format by billing it as a “US vs UK” competition between minor personalities from both sides of the Atlantic.

Channel 5, which is now owned by American media giant Viacom, signed a deal with Endemol earlier this year to continue airing the Big Brother format for another three years.

Channel and Endemol have insisted that they had not been aware of Ms Nguyen’s comments before she appeared on the programme this week and said it was investigating.

The Campaign Against Antisemitism called for Ms Nguyen to be removed immediately from the programme and criticised Channel 5 and producer Endemol Shine UK for selecting the 33-year-old American to appear.

The group in particular criticised a photomontage posted in 2013 on her Facebook page in which she appears in front of the Auschwitz death camp while scantily-clad wearing the Nazi emblem and a cap emblazoned with the skull symbol of the SS. The picture has since been removed.

Jonathan Sacerdoti, director of communications, said: “The British public has little time for attention-seeking Nazi sympathisers like Tila Tequila. Channel 5 and Endemol Shine UK ought to be ashamed of themselves for promoting such a deeply offensive person on prime time television.

Most memorable reality TV moments Show all 11 1 /11 Most memorable reality TV moments Most memorable reality TV moments Britain's Got Talent Violinist Natalie Holt threw eggs at judges during a performance in Britain's Got Talent because she thought Cowell has too much power and influence in the entertainment industry (2013) YouTube/ITV Most memorable reality TV moments Big Brother Jade Goody accused of racism after calling Bollywood star Shilpa Shetty ‘Shilpa Poppodom’ in Celebrity Big Brother (2007) YouTube/Channel4 Most memorable reality TV moments Big Brother Nikki hilariously impersonates Aiselyne for pretending to be a rude girl in the Big Brother diary room (2006) YouTube/Channel4 Most memorable reality TV moments X-Factor Chloe Mafia – drunk when she performed during bootcamp in X-Factor (2010). She also denied reports she was a prostitute. YouTube/ITV Most memorable reality TV moments X-Factor Girl punches her best friend on stage on X-Factor (2010) YouTube/ITV Most memorable reality TV moments Big Brother Michelle and Stuart caught having sex on camera in Big Brother (2010) YouTube/Channel4 Most memorable reality TV moments Come Dine With Me Come Dine With Me host Dawn falls asleep in her house forcing her guests to finish cooking her meal for her (2013) YouTube/Channel4 Most memorable reality TV moments Come Dine With Me The unforgettable moment a snake pooed on the dining room table in Come Dine With Me (2010) YouTube/Channel4 Most memorable reality TV moments I'm A Celebrity Gillian McKeith faints after being told she must take part in a Bushtucker trial on I’m A Celebrity (2010) YouTube/ITV Most memorable reality TV moments Dancing on Ice David Seaman drops Pam O’Connor on the head during rehearsals for Dancing on Ice (2006) YouTube/ITV Most memorable reality TV moments Big Brother Nasty Nick being rumbled in series one of Big Brother (2000) YouTube/Channel4

“Her repulsive writings make her a totally unacceptable participant for this programme. Channel 5 ought to remove her immediately from the programme and apologise fully for their enormous error of judgment. She should then be given the exact amount of public attention as she deserves: none.”

He added: “It is hard to understand how Channel 5 missed this information. Her comments have been covered very well by gossip websites in the past.”

In Channel 5’s online publicity material, Ms Nguyen, 33, claimed she was misunderstood. Asked what she expected British viewers to make of her, she said: “I think they think I’ll have this vapid, shallow, sexual image that is nothing more than that but I am actually not that. I am very goofy and I have a sense of humour that you might not understand right away. I am out there. I don't have a filter with what is on my mind. But I don't mean harm by it!”