He's chiefly known today as a singer-songwriter with a knack for ballads, but Christopher Cross is really an underrated rock guitarist — and during his early days on the Texas live circuit, he had such a solid reputation as a young axeman that he was tapped as an emergency replacement when Ritchie Blackmore fell ill before one of Deep Purple's early U.S. shows.

Cross recounts that little-known footnote from his career in the pages of the new book The Yacht Rock Book: The Oral History of the Soft, Smooth Sounds of the 70s and 80s. Compiled by author Greg Prato and due March 8, the retrospective contains first-person reminiscing from artists identified with the soft rock sub-genre. Cross, in an excerpt posted by TeamRock, reveals how he ended up taking the stage with the future classic rock legends.

As with so much of what happens in people's professional lives, Cross' Deep Purple moment was the result of who he knew — specifically a local promoter named Joe Miller, who was handling the Purple show and also "kind of managing" Cross at the time. As Cross recalls it, the band members were instructed to get vaccinated prior to the concert, which was being held at the Jam Factory in San Antonio on Aug. 28, 1970. Blackmore's flu shot had an adverse effect, leaving him unable to perform.

"They didn’t really want to cancel the show if they could help it. And Joe Miller," Cross recalled, "said, ‘Y’know, there’s this guitarist in town who’s a big fan of Ritchie’s and he could probably step in.’"

Directed by Miller's mandate, the other members of Deep Purple welcomed Cross to the lineup for the night. "I came down, and I had a Flying V and long hair, and I’m this big Ritchie fan. So we played the songs that I knew and then we jammed some blues. And they told the crowd Ritchie wouldn’t be there. It was a great moment for me," Cross added. "And then, when they left town, I went to the airport and got to meet Ritchie, and he thanked me for covering for him. He was cool."

Somewhat less cool — or at least possessed of a less-than-perfect memory — was keyboardist Jon Lord, who was asked about the night by Deep Purple's label boss when the band shared a record company with Cross decades later. Lord insisted it never happened, leaving Cross to seek out his longtime friend Eric Johnson for verification.

"I called up Eric, and I said, ‘Man, is this a flashback or something? Am I imagining this?’ He goes, ‘No way. I was there. We opened and you played with them. Jon Lord’s lying,'" said Cross. "This is something that Jon Lord wanted to forget and I wanted to remember. Because it was a nightmare for them. It was just horrible. ... And their star, Ritchie, was a pretty big part of it. But it’s a very cool thing."