Caesars Entertainment, the Las Vegas casino-owner, has struck a £2.9bn deal to take over William Hill.
The boards of the US firm and William Hill agreed a cash offer of 272p a share, compared with 273p at the start of Wednesday trading, subject to shareholders voting in favour.
US private equity firm Apollo had also made a bid to take over William Hill.
But Caesars said that if the UK company chose Apollo, it would jeopardise a joint venture between them.
Caesars owns a 20% stake in William Hill’s US operations, which also have exclusive rights to operate sports betting under the Caesars brand.
The US firm, which owns Caesar’s Palace in Las Vegas, is particularly interested in William Hill’s US bookmaking business which currently has 170 retail sites in 13 different states.
In August William Hill said it would not be reopening 119 of its UK High Street betting shops after the coronavirus shutdown, saying it did not expect customers to return in the numbers seen before the pandemic.
William Hill said its directors would “unanimously and unconditionally” recommend that shareholders accept the deal.
The Caesars Palace owner intends to find other owners for William Hill’s non-US businesses, including its more than 1,400 UK betting shops.
It said it would integrate the US business into Caesars with minimal job cuts.
The agreement comes soon after William Hill said it was inclined to recommend Caesars’ offer.
Roger Devlin, chairman of William Hill, said: “The William Hill board believes this is the best option for William Hill at an attractive price for shareholders.”
Caesars chief executive Tom Reeg said: “The opportunity to combine our land based-casinos, sports betting and online gaming in the US is a truly exciting prospect.”