Jeremy Clarkson has denied using the word n****r in what is the latest racism controversy surrounding the Top Gear presenter.
Clarkson, 54, is accused of using the word in a previous unseen clip of the BBC2 programme in a clip obtained by the Daily Mirror.
The footage, which was later edited out for the show, appears to show Clarkson choosing between two cars while reciting the nursery rhyme "Eeny, meeny, miny, moe..."
Clarkson is then alleged to have mumbled "catch a n****r by the toe".
The BBC said they have launched an investigation into the allegations. A spokesperson for the broadcaster said: "We've seen the story. The Mirror didn't approach us before publication. Clearly we will establish the facts before commenting."
Clarkson denied he ever said the word to his 3.2 million followers on Twitter.
The clip was taken from a show first aired on February 2013. In the broadcasted version of the episode, Clarkson says "catch a teacher by the toe" when choosing between the between Toyota GT86 and a Suburu BRZ.
The controversy emerged after Top Gear's executive producer Andy Wilmen expressed "regret" over Clarkson's use of the word slope during the show's Burma special in March.
Wilmen said the programme makers were not aware of the racist connotations the word has at the time of filming.
During the programme, Clarkson and co-hosts Richard Hammond and James May built a bridge over the River Kwai in Thailand.
After completing the bridge, the three stood at one side as an Asian man walked across it.
Clarkson then said: "That is a proud moment, but there's a slope on it." Hammond replied: "You're right, it's definitely higher on that side."
Wilman said: "When we used the word 'slope' in the recent Top Gear Burma special it was a light-hearted wordplay joke referencing both the build quality of the bridge and the local Asian man who was crossing it.
"We were not aware at the time, and it has subsequently been brought to our attention, that the word 'slope' is considered by some to be offensive and although it might not be widely recognised in the UK, we appreciate that it can be considered offensive to some here and overseas, for example in Australia and the USA."
He added: "If we had known that at the time we would not have broadcast the word in this context and regret any offence caused."
In the past, Clarkson and the other Top Gear presenters have been accused of making racist remarks about Mexicans.
In February 2011, the BBC was forced to apologise over comments which saw Hammond describe Mexican cars as "just going to be lazy, feckless, flatulent, leaning against a fence asleep looking at a cactus with a blanket with a hole in the middle on as a coat", and fellow presenter James May describing Mexican food as "like sick with cheese on it".
Clarkson fuelled the controversy in one of his Sun newspaper columns responding to the storm. He signed off with a joking which said: "Mexico doesn't have an Olympic team... because anyone who can run, jump or swim is already across the border."