Updated from 12:35 a.m. EDT

BALTIMORE ( TheStreet) -- Activist investor Nelson Peltz will be named a director of Legg Mason ( LM - Get Report) after accumulating a significant stake in the mutual fund firm.

Peltz will be elected Tuesday to the board, Legg Mason confirmed Monday in a press release.

Reports earlier said Peltz would be named a director after he acquired a 4.3% stake in the firm and pushed for a board seat, the Wall Street Journal said.

Peltz's New York hedge fund, Trian Fund Management, as part of Pelt's joining the board, has agreed to vote its shares in favor of Legg Mason's director nominees.

Trian holds 6.95 million shares of Legg Mason, the mutual fund firm said. Most of the stake was bought in the early summer when the stock was trading in the high-teens and low 20s, the Journal notes. The stock closed Friday at $31.90, up $1.19, or 3.9%. It has risen about 45% year-to-date and has more than tripled from its March lows.

Trian is said to be particularly interested in Legg Mason's Western Asset Management fixed-income business, which along with BlackRock ( BLK - Get Report) and Pacific Investment Management, has a leading presence in the business of managing bond portfolios, according to the newspaper. The Western unit, with about $500 billion, is about 72% of the firm's assets.

-- Reported by Joseph Woelfel in New York .

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