Image copyright EPA Image caption Mr Johnson is a major Republican Party fundraiser

US President Donald Trump has announced he will formally nominate NFL tycoon Woody Johnson to be US ambassador to the UK.

The billionaire philanthropist and heir of the Johnson & Johnson pharmaceutical giant, who is 70, has known Mr Trump for many years.

However, Mr Johnson, a major Republican fundraiser, originally backed Trump rival Jeb Bush in Republican primaries.

He will require Senate confirmation before he can take up the post.

Mr Trump first raised the idea of nominating him in January, on the eve of his inauguration.

The post of Ambassador of the United States to the Court of St James is viewed as a plum diplomatic appointment, traditionally given to only the most prolific donors or best-connected political insiders.

UK Prime Minister Theresa May's spokeswoman welcomed the nomination, Reuters news agency reports.

"We are looking forward to working with the new US ambassador once that is confirmed," she said.

"His close personal relationship with the president shows the commitment of the administration to the special relationship between our two countries."

The people around Donald Trump

Who is Woody Johnson? By Anthony Zurcher, BBC News, Washington

Although he's probably best known as the owner of the long-suffering New York Jets team in the National Football League, Mr Johnson is quite familiar in conservative circles, having contributed millions of dollars to Republican causes.

Like many big-money donors, Mr Johnson was an early supporter of Governor Jeb Bush's presidential campaign and was once cited by Donald Trump as an example of how the former Florida governor was in the thrall of big-money interests. Mr Trump even fired off a tweet mocking the Jets' lack of success.

The heir to the pharmaceutical and consumer products company Johnson & Johnson threw his support behind Mr Trump when it was clear he would be the party's nominee, however. He then served as a loyal fundraiser and adviser during the general election campaign.