If Walt Disney Co. buys most of 21st Century Fox, that would be a "dream come true," an industry analyst said.

21st Century Fox has been holding talks to sell most of the company to Disney, leaving only an entity focused on news and sports, CNBC reported Monday, citing sources familiar with the situation.

Such a sale would be a "dream come true," Laura Martin, senior analyst, entertainment and internet at Needham, said on CNBC's "Power Lunch" Monday. Martin has a hold rating on the stocks of both companies.

She estimated such a deal would cost Disney $20 billion to $30 billion.

"Putting these assets under Disney's hands will make them a lot more money," Martin said. "At the end of the day, Fox will get more money than it could have by it operating those businesses and Disney will make more at the outset."