Image copyright Getty Images Image caption Sir Tom Jones has remained close friends with Elvis' former wife, Priscilla Presley

Few people can say they really knew Elvis Presley - even fewer could call the King a true friend.

However Sir Tom Jones was among that close-knit group in which Presley would confide.

Presley's lifelong friend Jerry Schilling is organising a series of concerts marking the 50th anniversary of the performer's comeback tour.

He said the Welshman and Elvis would often spend evenings singing each other's songs to the early hours.

Mr Schilling said: "Elvis didn't really hang out with other entertainers that much, but if there was one artist that Elvis truly called a friend and hung out with the most, it was Sir Tom Jones."

Image copyright Alamy Image caption Tom Jones and Elvis at the Riviera Hotel in Las Vegas

The Treforest-born singer has said how Presley asked to meet him when they were both at a film studios in California.

"Elvis was always cautious about letting people get close and what their intentions were," said Mr Schilling.

"The people he had working for him were not there for the job, it was because he knew they could travel with him and he trusted them.

"But he was inspired by Tom and they became very good friends."

Image copyright Getty Images Image caption Jerry Schilling (second from right) and Elvis Presley meet President Nixon

Elvis greeted Sir Tom by singing one of the Welshman's songs during their first meeting in 1965.

He went on to regularly perform Jones' Delilah during his stage shows.

Mr Schilling told BBC Radio Wales: "We would all get together at a friend's house and they would sing songs at the end of the night. Tom liked to sing Elvis' "One Night With You"

"They even went on vacation together to Hawaii and spent lots of time together in Las Vegas."

Image copyright Getty Images Image caption Sir Tom performed at Hyde Park on what would have been Elvis' 75th birthday

They stayed in touch with one another until shortly before Presley's death in 1977.

This year marks the 50th anniversary of Elvis' Las Vegas comeback in 1969.

Having spent the previous eight years in Hollywood, he returned with a month-long residency at the new International hotel - which sold out, breaking all box office records.