John Malone’s Liberty Global announced that it has completed the acquisition of British cable operator Virgin Media in cash-and-stock deal valued at $24 billion.

With the addition of Virgin Media, Liberty Global now will serve 25 million customers principally in 12 European countries. Virgin Media, the No. 1 cable operator in the U.K., has about 4.9 million customers.

Last month, Liberty Global announced the appointment of former News Corp. exec Tom Mockridge to run the company as CEO. Mockridge — who officially took the role Friday, replacing former topper Neil Berkett — reports to Liberty Global prexy and CEO Mike Fries.

On Tuesday, Liberty Global announced that Dana Strong, managing director of the company’s UPC Ireland operator, will become Virgin Media’s COO. She replaces Andrew Barron.

“This is a great day for customers, employees and shareholders of both Liberty Global and Virgin Media,” Fries said in a statement. “With superior network capacity, the fastest broadband speeds and innovative digital TV platforms, we’ve never been more excited about the growth potential and strategic direction of our business.”

Liberty Global reported revenue of $10.3 billion and net income of $387 million in 2012. The company’s operator holdings include UPC, Unitymedia, Kabel BW, Telenet and VTR, and its operations also include: Chellomedia, its content division; the Liberty Global Business Services commercial division; and the Liberty Global Ventures investment fund.