Boehly's group agreed a deal to buy Chelsea from Roman Abramovich for £4.25 billion ($5.3 billion) on May 7 and the sale has now been officially rubber-stamped.

"We are honoured to become the new custodians of Chelsea Football Club. We're all in, 100 percent, every minute of every match," Boehly told Chelsea's website.

Boehly's takeover ends Abramovich's 19-year reign as Chelsea owner.