Robby Krieger and John Densmore of the Doors recalled witnessing their shy and retiring singer Jim Morrison's transformation into his dynamic Lizard King frontman character as the band solidified in its early days.

You can watch the discussion in an exclusive clip from The Big Interview With Dan Rather below. The full show airs on AXS TV on March 20 at 9PM ET.

“[Morrison] had never sung before,” Densmore told Rather. “He'd said he heard a concert in his head, but he had never done this. So it's just a gift. ... But, in the beginning, he would face us … he couldn't even look out at the audience. But he gradually evolved into the Lizard King.”

Asked about Morrison's evolution, which turned him into one of rock's most charismatic and enduring singers, Krieger said it was probably always there. “I think he always had that in him – he was just waiting to let it out," he explained. "As he said, it was like a bowstring being drawn back for 21 years and then let go.”

The Doors recently released a DVD of their final filmed concert, Live at the Isle of Wight 1970, which was performed amid tensions within the band. “Our set was subdued but very intense,” Manzarek, who died in 2013, once remembered. “We played with a controlled fury and Jim was in fine vocal form. He sang for all he was worth, but moved nary a muscle. Dionysus had been shackled."