Robert Plant, 67, told a Los Angeles federal court that the song at the center of a federal copyright case was clearly his work as well as that of Zeppelin guitarist-songwriter Jimmy Page.
He recalled hearing "Stairway" in its infancy in the early 1970s at Headley Grange, a recording and rehearsal venue in Hampshire, Britain, that the band used.
"That particular evening, I sat with Jimmy by the fire, and I had this first couplet that fit with what he was playing," he testified, recounting the beginning lyrics of the famous song.
"I was really trying to bring the remote, pastoral Britain... the old, almost unspoken Celtic references into the piece," he added.
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'Stairway to Heaven' plagiarism trial underway
Plant was one of the last witnesses to testify in the high-profile case, with closing arguments set to begin on Wednesday before the jury retires to begin deliberating a verdict.
Plant and Page are being sued for allegedly stealing the anthem's melancholic opening guitar arpeggio from "Taurus," the first album of long-defunct LA psychedelic rock band Spirit.
Page testified last week that his chord progression had more in common with "Chim Chim Cher-ee", from the 1964 musical "Mary Poppins" than anything else.
'Musical building block'
Zeppelin bassist John Paul Jones has also rejected allegations that his bandmates had plagiarized parts of Spirit's 1968 track.
He told the court last week that he remembered first hearing what would become "Stairway" at Headley Grange as he and Page worked up an early arrangement.
Spirit guitarist Randy California, who penned "Taurus," long maintained he deserved a songwriting credit for "Stairway" but never took legal action and drowned in Hawaii in 1997.
A lawsuit filed by his trustee and friend Michael Skidmore two years ago seeks damages and claims California deserves a songwriting credit so that he can "take his place as an author of rock's greatest song."
At stake in the case are potentially millions of dollars in royalties collected in the three years prior to the filing of the suit through this month.
Music expert Lawrence Ferrara of New York University has testified that any similarity between "Stairway" and "Taurus" could also be found in music written by composers for more than 300 years.
"It's a musical building block," Ferrara testified, and "not a relevant similarity."
Zeppelin opened for Spirit when the hard rockers - Plant, Page, Jones and the since deceased John Bonham - made their US debut on December 26, 1968 in Denver.
But the surviving members have submitted testimony that they never had substantive interaction with Spirit or listened to 1967's "Taurus" before recording "Stairway" in December 1970 and January 1971.
The lawsuit lists disputes over 16 other Led Zeppelin songs, many of which were settled by giving the complainant a songwriting credit and royalties, including classics "Whole Lotta Love" and "Babe I'm Gonna Leave You."
