As saxophone supremo Charles Lloyd pushes out a cascade of soaring notes, jazz aficionados in Montreux sway in rapture.

The legendary American musician was back on stage at the opening of this year's Montreux Jazz Festival, half a century after he headlined the first festival in the idyllic Swiss town in 1967.

He was followed by fabled jazz pianist Monty Alexander, who first played Montreux in 1976, and who returned to revisit the celebrated recording he made on that occasion called "Montreux Alexander".

Forty years on, his fingers fly over the keys, prompting some in the 300-seat venue to jump out of their seats and start dancing in the aisles.

"It was just a mythical concert," enthused Jacques Emery, a 69-year-old pensioner.

"I was floating. I think actually I levitated in my seat."

That was the kind of almost spiritual experience Lloyd, 78, was aiming for, he told AFP ahead of Thursday's concert, saying he himself receives the music from a higher authority and just allows it flow through him.

"I like to go as an empty vessel as possible and let the creator fill me up and fill all of us," he said, smiling behind his dark glasses.

The septuagenarian sways and grooves on stage like a man half his age, arching his back and lifting his knee up to meet his saxophone.

"I'm drunk with the music and it informs me and it elevates me and puts me in the zone," he said.

'When giants roamed'

Lloyd, who was one of the first jazz artists to sell more than a million copies of a record, first began playing with stars as a boy growing up in Memphis.

"I've been blessed to play with some of the greatest musicians on the planet. I've been around when giants roamed the earth," he said, listing blues legends like Howlin Wolf and BB King among those he has accompanied.

Jazz greats like Duke Ellington, Johnny Hodges and Harry Carney, who used to stay at his childhood home when they came to town, also played a formative role in his musical education.

"They told my mother to have me be a doctor, lawyer or Indian chief, not this (jazz musician), because it's too hard," he said, "But I was bit by the cobra, so it was too late."

Jamaica-born Monty Alexander, 72, has also played with a number of luminaries over the course of his career.

"I recorded with Tony Bennett, (and) I knew Miles Davis very well," he told AFP.

Like Lloyd, he also found a mentor in the Duke.

"Duke Ellington was one of the people that wrote a letter to the US immigration to allow me to stay in America," he said. "The other one was Frank Sinatra."

Alexander, who taught himself to play the piano as a boy but never learned to read music, says he considered himself "so fortunate to do something that didn't feel like I was working".

"I still feel like it's a dream. How can you make music and get paid for it?" he said.