Hilton Hotels Corp. on Friday said it is in discussions to acquire the hotel division of UK-based Hilton Group Plc, in an all-cash deal reported to be worth about $6.3 billion.

The deal would reunite the international and North American Hilton hotel brands under one roof in the U.S. at Hilton Hotels for the first time in more than 40 years. Beverly Hills-based Hilton Hotels sold the international rights of the Hilton brand in 1964, and the companies have been separate ever since. The two companies share an alliance to cover joint marketing, reservation and loyalty programs, and have discussed a merger for a number of years.

Hilton Group’s Ladbrokes betting business is reportedly not part of the deal.

Hilton Hotels Corp. has more than 2,300 hotels it either owns, manages or franchises, while Hilton Group’s portfolio includes more than 400 hotels under the Hilton and Scandic brands. Ladbrokes acquired the Hilton business outside the U.S. in 1987, and changed its name to Hilton in 1999 after it acquired the Scottish casino and hotel operator Stakis.

Hilton Hotels said in a statement that it will not make any further announcements with respect to the discussions until either a definitive agreement is reached or the talks end.

Shares of Hilton Hotels fell 6.2 percent to settle at $19.95 on Friday.