Naomi Campbell is bringing a privacy case in London's High Court.
The 31-year-old supermodel is suing The Mirror for breach of confidence and/or unlawful invasion of privacy after it published a photograph of her leaving a Narcotics Anonymous meeting a year ago.
The newspaper said Campbell had been receiving regular counselling in a "courageous bid to beat her addiction to drink and drugs".
The Streatham-born model is expected to give evidence before Mr Justice Morland during the estimated five-day case, which will not involve a jury.
Piers Morgan, the editor of The Mirror - which is to defend her claim - has also said he will take the stand.
The Mirror's publishers MGN are also due to be involved in another privacy case when the Lord Chief Justice, Lord Woolf, was set to hear an appeal by the Sunday People against a series of rulings made last year by High Court judge, Mr Justice Jack.
The case centred on the right to privacy of a professional footballer who had allegedly had extra-marital affairs with two young women.
The newspaper will challenge the ruling that the law should, in the context of modern sexual relations, afford the protection of confidentiality to facts concerning sexual relationships outside marriage just as within marriage.