The National Portrait Gallery in London has received its largest single donation to date, a £5m gift from US billionaire Randy Lerner.
Randy Lerner bought Aston Villa football club in 2006
Mr Lerner, who bought Aston Villa football club in 2006, will give the money over the next three years.
The ground floor galleries will be named after Mr Lerner in recognition.
Half of the cash will go towards buying new portraits to improve the collection and the rest will be spent on research, display and outreach work.
Mr Lerner has supported the gallery since 2002 and the money will help build up the Portrait Fund at a time when art prices are rising and funds for acquisitions are limited.
The Lerner Foundation was created by the family of Alfred Lerner, Randy's father, who died five years ago.
"On behalf of my mother and my sister it is an enormous privilege to express our support for the National Portrait Gallery financially," Randy Lerner said.
"We are enthusiastic supporters of the gallery's director and the board for their inspired and creative management of the gallery's collection and acquisition programme."
Gallery director Sandy Nairne said: "I am delighted that the Lerner family is expressing such confidence in the future of the National Portrait Gallery.
"This builds on the tradition of key support in recent years of a number of major benefactors."