But Elizabeth Edwards canceled the call, according to Davis.
Thursday afternoon's testimony featured Huffman, the interior designer from Monroe, North Carolina.
Huffman, a longtime friend of Mellon, said he understood money was welcomed because "Mr. Edwards needed financial support for a poverty center."
Mellon also saw Edwards as a possible presidential candidate when she started making the payments, Huffman said.
In all, Mellon who will turn 102 in August, gave $725,000 for something Huffman said she knew nothing about: Payment for Hunter's expenses.
Huffman suggested Mellon didn't consider her donations as specifically intended for the campaign.
The witness elicited a laugh from the courtroom audience when he admitted that Mellon said she knew individual contribution limits the 2008 election cycle but that Mellon considered the limits "a little low."
In 2008, the Federal Election Commission limited an individual to a contribution of $2,300 to each candidate or candidate committee in the primary election and $2,300 in the general election.
Huffman, who said he never took any of the money for himself, talked about how the payments were made.
He described the process for getting cash to one of Edwards' key staffers, Andrew Young, as a "furniture business."
Mellon wrote several checks payable to Huffman ostensibly for a table, chairs and a bookcase. Huffman said he signed the checks, but instead of cashing them, he handed them over to the family of Andrew Young, the prosecution's star witness.
Young's wife, Cheri, endorsed the checks, but signed her maiden name.
Mellon didn't want her lawyer to find out about the checks because he was always on the lookout for examples of Mellon giving away too much money, according to Huffman, who said the whole thing "just didn't feel correct."
Cheri Young testified Monday that Edwards told her that using money from one of his benefactors to pay his mistress's expenses was legal. Young said that she felt "disgusted" after being asked to endorse and deposit checks from Mellon.
Edwards' attorneys have said that Andrew Young was involved in a ruse to extract hundreds of thousands of dollars from donors for his personal use.
The defense argues that the money Edwards received from Mellon and Baron was for personal reasons: to protect Elizabeth and his family from public humiliation. Edwards has said his actions were wrong but insisted that they were not illegal.