Liberty Global says the deal with Virgin Media means the company will have a total of 25 million customers in 14 countries.
It is already the largest cable operator in most of its 11 European markets. But the majority of revenue is expected to come from five countries - the UK, Germany, Belgium, Switzerland and the Netherlands.
Liberty Global says it plans to continue investing in Virgin's broadband network.
More top news
Around 760 out of the 4,200 foreign offenders living freely in the UK have disappeared from sight, according to a leading watchdog.
Schools and nurseries are being called on to help check children have brushed their teeth.
Changes in gait could prove to be an early sign of Parkinson's disease, according to a new study.