(CNN) -- Actress Mia Farrow testified Monday that supermodel Naomi Campbell named Charles Taylor as the person who presented her with a diamond.
Farrow was testifying at the war crimes trial of Taylor, the former president of Liberia who prosecutors allege funded a brutal civil war in Sierra Leone using blood diamonds.
A so-called blood diamond is mined in war zones and used to fund rebels and warlords. The stones have fueled bloody conflicts in Africa for more than a decade.
Farrow's testimony at the United Nations-backed Special Court for Sierra Leone contradicted that of Campbell, who took the stand last week.
During her appearance, Campbell said she didn't know who sent her stones, which were delivered to her room in Pretoria, South Africa late at night.
But Farrow told prosecutors: "She said that in the night she had been awakened. Some men were knocking at her door. They were sent by Charles Taylor and they had given her a huge diamond."
Both Farrow and Campbell were guests at a dinner hosted by Nelson Mandela in 1997, which Taylor also attended.
The next morning, Campbell told the tribunal, she shared the story of receiving stones with her then-agent, Carole White, and Farrow.
"Well, that's obviously Charles Taylor," one of them said. Campbell didn't recall who said it.
Then, one of them added, "Well, obviously, they are diamonds."
Campbell said she assumed the stones came from Taylor, but testified that she wasn't sure.
After her testimony, prosecutors said they would present two witnesses who would dispute Campbell's story.
"Two other witnesses will also testify about these events.... there are significant differences between those accounts and Ms. Campbell's account," the prosecution said in a statement.
Farrow's testimony did just that.
Taylor, 62, was president of Liberia from 1997 to 2003. The war crimes charges against him stem from the widespread murder, rape and mutilation that occurred during the civil war in Sierra Leone, fought largely by teenagers who were forced to kill, given addictive drugs to provoke violent behavior and were often instructed to rape and plunder.
Taylor is charged with five counts of crimes against humanity, including murder, enslavement and sexual slavery and violence. He also faces five counts of war crimes, including acts of terrorism and torture, and one count of other serious violations of international humanitarian law.
He has pleaded not guilty.
Prosecutors had rested their case against Taylor in February 2009 but reopened it to call Campbell to testify after learning in June of that year that Taylor had given the supermodel a diamond.
When arguing to reopen the case, prosecutors said Campbell's testimony would prove that the former president "used rough diamonds for personal enrichment and arms purchases," according to papers filed with the U.N.-backed court.
Taylor has testified that he never handled the precious stones.