'Unforgettable': Celine Dion recalls 'Tell Him' duet with Barbra Streisand

Celine Dion is sharing why her song "Tell Him" with Barbra Streisand was a special one to make.

For the song's 27th anniversary, Dion shared the memory in an Instagram post on Friday and said she never thought she'd have the opportunity to sing with Streisand. The song appeared on Dion's "Let's Talk About Love," album and Streisand's "Higher Ground," album, both of which were released in 1997.

"Never in a million years would I have thought or had the guts to ask to sing a duet with Barbra Streisand. Never," Dion began. "But somehow, through the persistence of David Foster (who could ask anything of anyone), this incredible opportunity fell into my lap."

"I was just in complete admiration of her talent as an actress, as a singer, and as an icon," she continued. "Never could I have imagined something like this happening to me."

Dion said she remembered feeling "nervous" about singing with Streisand and was in awe of her talent from the very start.

"She has four pianos in her vocal cords and can defeat everything vocally while I can barely hit certain notes," she said. "She has such unparalleled vocal talent that I felt completely outmatched. But, I was determined to do justice to her song and to not disappoint her in any way."

But when they got to the studio to record the song, Dion recalled Streisand being "sweet, warm and welcoming."

"She took me aside at one point as we were rehearsing, and I was like, 'Oh… my… God.'"

"Performing this duet with Barbra was a career-defining, unforgettable experience," Dion said. "I will always cherish that memory, and I can only hope that I was able to do justice to her incredible artistry."

"I am so deeply honored to have collaborated with a true musical legend and the memory will live with me forever," she added.

In a 1997 behind-the-scenes interview with Dion and Streisand, Streisand called Dion's voice a "gorgeous instrument."

"You have a great heart and sensitivity that it just makes me proud to sing with you," she told Dion.