The Martha-Donald feud escalated Tuesday as Donald Trump fired off a blistering letter, accusing Martha Stewart of lying in her interview with Newsweek in which she claimed that NBC's original plan was to put Trump's version of The Apprentice on hiatus and replace it with hers. Stewart had told the magazine that the plan was for her to "fire" Trump in the first episode and take over as the sole host. "Essentially, you made this firing up just as you made up your sell order of ImClone," Trump wrote, referring to the case that sent Stewart to prison for lying to federal investigators. (Newsweek reported that Apprentice producer Mark Burnett confirmed that the scenario described by Stewart was indeed discussed. "Thank God that didn't happen," he added.) Trump's letter also criticized Stewart's performance and said her show "lacked mood, temperament and just about everything a show needs for success. I knew it would fail as soon as I first saw it. ... Between your daughter, with her one-word statements, your letter writing and, most importantly, your totally unconvincing demeanor, it never had a chance -- much as your daytime show is not exactly setting records." Late Tuesday, Stewart responded: "The letter is so mean-spirited and reckless that I almost can't believe my longtime friend Donald Trump wrote it. I am very proud of the work we did." Appearing later on CBC's The Big Idea with Donny Deutsch, Trump remarked, ""Of course the letter was mean spirited, but I think what she did was mean spirited."