Taxi firm Addison Lee has snapped up US rival Flyte Tyme in a deal understood to be valued at 25 million US dollars (£20 million).
The private equity-owned company said the move would bolster global sales to nearly £400 million and cement its position as one of the world's biggest chauffeur firms.
Flyte Tyme is based in New Jersey and has a turnover of 65 million US dollars (£53 million), with 525 staff and 375 drivers.
It comes after Addison Lee boosted its global footprint in June last year by buying Tristar Worldwide, which has operations in 80 countries.
The London-based taxi firm has been looking to keep pace with the astronomical rise of Uber, which has radically shaken up the industry with its ride-hailing smartphone app.
Andy Boland, chief executive of Addison Lee, said the Flyte Tyme deal was an important moment for the executive car industry.
"Flyte Tyme has deep expertise and an extensive affiliate network in the United States," he said.
"By combining Flyte Tyme's North American presence with Tristar's global operations and Addison Lee's digital booking platforms, we can now truly lead the ground transportation industry providing, for the first time, global managed ground transportation services through a single platform."
The tie-up will hand Addison Lee a combined US fleet of 400 premium vehicles and more than 17,000 executive cars through "affiliate partners".
It will boost annual American revenues to more than 100 million US dollars (£82 million) per year.
As part of the move, Flyte Tyme Worldwide Transportation's CEO, Timothy Rose, will become the CEO of Addison Lee North America.
He added: "Through this acquisition, we will be able to leverage our combined technology and client service capabilities to deliver a truly global service for our clients."
Addison Lee, which is owned by US private equity firm The Carlyle Group, was founded in Battersea in 1975 and has grown to become Europe's largest private hire car service company, carrying out 10 million journeys per year.