Famed reporter Mike Wallace has picked sides in the guardianship dispute over philanthropist Brooke Astor.

Mrs. Astor’s only son, Anthony Marshall, received a letter from Mr. Wallace in which he writes of Mr. Marshall’s devotion to his mother, a spokeswoman for Mr. Marshall said.

From the beginning, the guardianship dispute over the 104-year-old woman has attracted responses from several of the country’s most prominent citizens. The Daily News reported that court papers filed two weeks ago include affidavits from Secretary of State Kissinger, David Rockefeller, and Annette de la Renta in support of wresting the guardianship from Mr. Marshall.

Mr. Wallace, whose retirement from “60 Minutes” this year made headlines, is backing Mr. Marshall, according to the spokeswoman for Mr. Marshall, Brooke Morganstein.

In a three-paragraph letter dated yesterday, a copy of which Ms. Morganstein supplied via e-mail, Mr. Wallace wrote: “It’s always been clear to me that Anthony is a devoted son, adores his mother and has given her all the attention, concern and love that a son could offer.” He continues: “In light of what I’ve seen, I am perplexed by the attacks leveled against Anthony. I believe they are completely undeserved. Any parent would be thankful to have a son like Anthony.”

The court papers reportedly accuse Mr. Marshall, 82, of cutting the number of attendants waiting on his mother and of not filling her prescriptions, among other allegations. With the court papers, Mr. Marshall’s own son, Philip Marshall, has sought to have the guardianship transferred to Ms. de la Renta, the wife of fashion designer Oscar de la Rental.

Mrs. Astor headed the Astor Foundation, which was responsible for giving nearly $200 million to charity.

Mr. Wallace writes that he has known Anthony Marshall “for many years” and Mrs. Astor “for even longer.”

Ms. Morganstein was unable to provide further details about Mr. Wallace’s relationship to the family.