An agency has denied that Big Brother contestant Makosi Musambasi is an actress they supplied for the show.
Makosi paid to sign up to the agency
Makosi placed her details on the Envenio website, which aims to help people get work in the media.
Envenio admitted sending Makosi details of the Big Brother auditions, but denied making her audition tape or fast-tracking her into the house.
Makosi is one of four finalists left in the house hoping to win a prize of £50,000 on Friday.
The Sun newspaper has claimed a £609.68 bill was sent to the show's makers Endemol for studio hire, tapes, and photos - allegedly relating to Makosi's audition tape.
The paper says it has a copy of an invoice from Envenio's sister company, The Casting Suite, to Endemol.
But both Envenio and Endemol have said the invoice was for a separate job unrelated to the Big Brother housemates.
A spokesman for Endemol said: "Nothing untoward has gone on and Makosi went through the same audition process as anyone else."
Envenio chief executive Paul Booth denied the firm had made her a professional audition tape for Makosi.
He said: "As far as we know, Makosi is not an actress.
"She signed up for our new faces section, which is for members of the public who aspire to be involved in the business. She put her details on our website.
"We emailed Makosi details of the Big Brother auditions, just like we emailed a lot of our members... it is no different to a company walking down the street looking for people.
Eugene has accepted half the prize money
"The invoice is from our sister company, The Casting Suite, and was for a completely separate job we did for Endemol."
Mr Booth said Envenio had supplied members of the public for a number of Channel 4 programmes, such as A Place In The Sun, and had supplied film extras.
Channel 4 issued a statement which said: "Makosi went through the same audition process as every other housemate and was not fast-tracked in any way.
"The Casting Couch invoice printed in today's Sun relates to the casting for Channel 4 on-air trails to promote Big Brother's Big Mouth."
Craig Coates was unexpectedly evicted from the Big Brother house on Wednesday night, after getting just 4.1% of the public vote to win.
In another twist, Big Brother offered finalist Eugene Sully the chance to take half the cash prize now, leaving the other half for the winner.
He accepted the offer - unaware that if he had rejected it, the prize pot would have doubled from £100,000 to £200,000.