Ms Thompson, 35, always said marriage was a huge risk, but the self-confessed optimist hoped that her union with fellow actor and director Kenneth Branagh, 34 - one of the most successful partnerships in the history of British film and theatre - would run and run.
As she stood dishevelled before an army of photographers at her west London home - hours after a Sunday tabloid headlined her alleged relationship with actor and recent co-star Greg Wise - she played tired and emotional for real.
Asked to repeat an earlier statement on the end of the six- year run, Ms Thompson managed: "I think it said 'due to the pressures of work'..." before trailing off. She said she could not string a sentence together, and refused to comment on her relationship with Mr Wise, 29, who stars with her in Sense and Sensibility, the film of the Jane Austen novel for which she wrote the screenplay.
Friends claimed that the marriage had been over for months, and blamed the pressure of work. Branagh had joked that he had to make an appointment to see her and that she went to bed with her Oscar. She had said she wanted children but that Ken was so tired "all his sperm are on crutches".
For those who revelled in the on and off-screen love affair the news was a tragedy of Shakespearean proportions. But Ms Thompson has admitted she was aware that the partnership's apparent combination of off-screen domestic bliss and commercial success was too rich for some. It is claimed that the couple spent fewer than 100 days together at their London home.
In a statement issued on Saturday night they said they had decided with great sadness to separate but that the split was entirely amicable. "Our work has inevitably led to our spending long periods of time away from each other, and, as a result, we have drifted apart."
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