WASHINGTON (AP) — Alaska U.S. Sen. Ted Stevens denied scheming to hide $250,000 in home improvements and other gifts from a corrupt businessman, taking the stand Thursday in his own defense at a corruption trial blocks from the U.S. Capitol.

When asked by his lawyer Brendan Sullivan whether he thought his disclosure forms were accurate when he signed them, the Alaska political patriarch replied, "Yes, sir."

Stevens, wearing an American flag pin on the lapel of his dark-colored suit, then responded with a soft "No, sir" when Sullivan asked whether he had engaged in any scheme with anyone to hide any gifts.

Stevens, 84, was the final witness in his defense against charges that he lied on Senate financial disclosure forms to conceal improvements to his modest chalet and other gifts from Bill Allen, a longtime friend and former chief of the oil services company VECO Corp.

Before taking the stand, Stevens — a plain-talking, gruff man whose trademark "Incredible Hulk" tie symbolizes his temper and reputation in the Senate — was told by U.S. District Judge Emmet Sullivan that he didn't have to testify.

"It's a privilege and a duty," Stevens replied while being sworn in.

Defense attorneys have said Allen kept Stevens in the dark about additional work done on Stevens' Alaska home at Allen's expense. Stevens was too busy to notice anything amiss as workers transformed his tiny A-frame cabin into a spacious two-story home.

"He works all the time," testified his wife, Catherine, a lawyer who married Stevens in 1980. "He's a classic workaholic."

Catherine Stevens also testified earlier Thursday that she was in charge of the renovation of their Girdwood, Alaska, cabin and that they paid every bill they received — $160,000 in all.

She described Allen as a friend who volunteered in 2000 to keep an eye on the renovation of their mountain cabin while they were away in Washington. She said she believed employees of Allen she later spotted at the site were being paid by the contractor — not Allen.

The contractor was "the one responsible for all renovations," she said.

During her testimony, the defense displayed invoices from the contractor for tens of thousands of dollars in labor and materials, and the checks she signed to pay them. She claimed Allen often crashed at the home and added some extras, including an expensive gas grill, without her approval.

When she first saw the grill, "I was very angry," she said. "It was a fire hazard and I didn't want it on my deck."

Prosecutor Brenda Morris jousted with the witness about her actual involvement with the renovation, with Mrs. Stevens saying she never interviewed the engineer who drew up the plans for the renovation, accepted the contractor on the word of Allen and never got a contract with the plumbers or electricians.

The work on the chalet was done by "people you didn't contract with, didn't know and assumed were doing the work?" prosecutor Brenda Morris said.

Morris also questioned Mrs. Stevens about her husband's Senate staff walking their dogs, paying their credit card bills, cutting their grass and doing other personal work for her family.

"Sometimes," said Mrs. Stevens, who added that if they did, the staffers were paid.

Allen became the government's star witness after pleading guilty to bribing Alaska state legislators. Earlier in the trial, Allen testified that Bob Persons, a restaurateur neighbor who helped monitor the project, told him the senator's occasional demand for bills was a ruse.

Testifying for the defense, Persons denied making the remark. He told the jury Thursday that he had been bullied by an FBI agent who came to his home in 2006 to grill him about the senator's home.

"It was like being mentally water-boarded," he said.

Stevens, the longest-serving GOP senator, has languished in the courtroom in Washington for more than three weeks as a Democratic opponent back home, Anchorage Mayor Mark Begich, mounts a strong challenge to the seat the senator has held for 40 years.

Hawaii U.S. Sen Daniel Inouye testified in the case last week as a character witness on behalf of Stevens.