Family-owned candy giant Mars, whose brands include M&M's and Snickers, is nearing a deal to acquire Kellanova, maker of snacks such as Cheez-It and Pringles, for nearly $30 billion, a person familiar with the matter told Reuters on Tuesday.

Mars will pay $83.50 per share in an all-cash deal for Kellanova that is set to be announced on Wednesday, the source said, requesting anonymity since discussions were confidential.

The offer represents a near 33% premium to Kellanova's close on Aug. 2, the day before Reuters first reported that Mars was exploring a deal for the Pringles maker. Shares of the company were up 8% at $80.54 in premarket trading on Wednesday.

Kellanova and Mars did not immediately respond to Reuters' requests for comment.

The deal for Kellanova comes as sales growth at U.S. packaged food companies including Kraft Heinz, Mondelez and Hershey have taken a hit as budget-strapped customers hunt for cheaper, private-label alternatives to pricier branded items.

This has spurred dealmaking in the packaged food sector as companies seek scale to weather the impact of price inflation and weight-loss drugs weighing on demand.

The potential Kellanova deal would be the biggest ever for Mars, dwarfing its $23 billion takeover of Wrigley in 2008.

It would bring under one roof a slate of popular consumer goods brand including Mars' Twix, Bounty and Milky Way chocolates as well as Kellanova's snacks portfolio of Pop-Tarts, Rice Krispies Treats and Eggo frozen waffles.

The acquisition is not expected to go through too many antitrust roadblocks due to the limited overlap between the two companies' offerings, legal experts had told Reuters.

Kellanova, which split from WK Kellogg Co last October, is rooted in a salty snacks business in the U.S. and around the world, and selling cereal outside of North America. WK Kellogg was left with the North American cereal business of Kellogg, the original parent company.

The Wall Street Journal reported the terms of the deal earlier on Tuesday.

(Reporting by Mrinmay Dey and Aishwarya Venugopal in Bengaluru and Anirban Sen in New York; Editing by Mrigank Dhaniwala and Sherry Jacob-Phillips)