Caesars Entertainment announced Thursday it had closed a £2.9bn ($3.7bn) acquisition of British bookmaker William Hill, concluding one of the largest mergers in modern gaming history.

Earlier this week, the High Court of Justice in England and Wales approved the deal, putting forth the final regulatory stamp.

Caesars is expected to greatly grow its US sports betting footprint. William Hill and Caesars collectively operate sports wagering in 18 US jurisdictions including the presence of mobile sports wagering in an industry-leading 13 markets.

William Hill runs more than 170 retail sportsbooks, a 29% market share in the US.

Caesars said in a statement the deal will “maximize the opportunity within sports betting and online gaming in the US”.

Caesars will give William Hill customers access to the company’s rewards program, which includes the opportunity to build tier status at Caesars properties.

“We are thrilled to complete the acquisition of William Hill, combining two of the premier operations in the sports betting and online gaming industries under one roof,” said Tom Reeg, CEO of Caesars Entertainment. “We look forward to announcing future sports partnerships that will drive long-term growth.”

During a March hearing in front of the Nevada Gaming Commission, Reeg indicated Caesars only wants to own William Hill’s American operations and is willing to sell off the UK bookmaker’s international business. He said Caesars would begin to unload William Hill’s international portion soon after the transaction closed.

Caesars is less than a year removed from a $8.5bn merger with Eldorado Resorts that grew the company’s market cap to approximately $20bn.