The purchase gives Heineken 82 percent of the prized Asia Pacific Breweries (APB)
Amsterdam-based Heineken already owned 42 percent of APB, which runs 24 Asian breweries, and buying F&N's 40 percent stake will help it to defend its turf which is under threat from Thailand's second-richest man.
F&N's board, whose chairman Lee Hsien Yang is the younger son of Singapore's elder statesman Lee Kuan Yew, will recommend the S$50 an APB share deal to its shareholders, Heineken said in a statement.
The Dutch company will now mop up minority shareholders at a similar price to make the total purchase worth about $6 billion.
Control of APB is vital for Heineken, the world's third largest brewer, as this will raise the proportion of its total profits from the fast-growing Asian market to 15 percent from 6 percent, while boosting the growth rate of the whole group.
By winning APB, Heineken gets ownership of Tiger, Bintang, Anchor and other brands of beer plus two dozen breweries in 14 countries including Singapore, Malaysia, Indonesia, Vietnam, Thailand and Cambodia. However, the biggest brand APB brews is Heineken itself, which accounts for 30 percent of its volumes.
Heineken shares jumped to a record high earlier after Reuters reported the deal, and when official confirmation came through later they hit a fresh high of 46.30 euros. They were up 3.6 percent at 46.03 euros by 1355 GMT.
The Dutch group had given F&N a Friday deadline to agree a sale after a two-week offer period, and both F&N and ABP shares were suspended on Thursday and Friday as a deal appeared close.
Heineken began brewing Tiger with F&N in the 1930s but that partnership hit the rocks after Thai Beverage
The investment by Charoen, who is seeking to expand his own Chang beer business in Asia, pushed Heineken into an offer for APB as it saw its position in Asia coming under threat.
The Heineken deal could prompt a breakup of F&N with Coca-Cola
That could pit Coca-Cola against two sizeable Asian brewers, Thai Beverage and Japan's Kirin Holdings <2503.T>, which have their own interests to protect as F&N shareholders.
F&N shares have jumped 31.5 percent this year to close at S$8.15 on Wednesday but have come off a record S$8.49. APB shares, which last traded at S$49.50, have surged 71.9 percent since the start of the year, and the offer price of S$50 was at a 45 percent premium to month ago levels.
(Writing by John O'Callaghan in SINGAPORE; Additional reporting by Saeed Azhar in SINGAPORE, Denny Thomas in HONG KONG, James Topham in TOKYO and Martinne Geller in NEW YORK; Editing by Ryan Woo and David Stamp)