Yacktman, which holds 14.8 million shares of Dell, said it believes Dell founder and Chief Executive Michael Dell's $24.4 billion buyout offer is depressing the stock.
"A change in the board of directors could significantly improve this and other issues and lead to enhanced shareholder value," Yacktman said in statement on Tuesday.
While Yacktman's support could bolster Icahn's plan, the firm's stake in Dell is only about 0.85 percent, and is not enough to make a material difference on its own.
Dell is at the center of a battle, with Michael Dell and private equity firm Silver Lake on one side, and Icahn and Southeastern Asset Management on the other.
Icahn and Southeastern's proposal would see shareholders tender 1.1 billion shares at $14 each. For that bid to be put to a vote, shareholders must reject Michael Dell's proposal and then elect a new slate of directors put up by Icahn.
Michael Dell and Silver Lake want to take the company private at $13.65 per share. On Monday, they gained a key backer in shareholder advisory firm ISS, which recommended their bid.
ISS said Michael Dell's offer "transfers the risk of the deteriorating PC business and the company's ongoing business transformation to the buyout group."
Icahn and Southeastern said they disagree with the ISS recommendation and would vote against Michael Dell's buyout offer.
(Also see: Dell takeover battle: All you need to know)
© Thomson Reuters 2013