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"I wrote this song in real time as the series developed," the songbird told Perez Hilton. "I'm so excited! I can't believe it!"
The show chronicles the Canada native's process as she penned the tune and worked to regain her self-confidence and will to perform. "I've trapped my own voice, and now I've got to unwipe all that," she told Oprah Winfrey earlier this year. "I really can't imagine not singing again."
In this Sunday's (June 5) episode, Shania participates in a one-on-one vocal training session with coach Eric Vetro, before working with producer David Foster to discuss working on the new tune. Watch it at 10:00 PM ET/PT on OWN.
Also expected in the series finale, titled 'Endless Love,' the singer-songwriter marries Frédéric Thiébaud, and shares never-before-seen footage from their wedding in the Bahamas.
"Fred is not only nice, he's incredible," Shania gushed to Redbook magazine. "He's attentive, brighter than God should ever allow any one man to be, funny, romantic, and cute as heck. Most of all, he shows what he feels, and that's a quality that could come in any shape or size and be admired -- it just so happens that Fred has a very gorgeous shape. He's too good to be true, only he's real! Good for me, is all I can say, and I'm loving every minute of it."
In addition, the episode will show Shania as she records a duet of 'Endless Love' with Lionel Richie.
The 'Why Not? With Shania Twain' finale airs Sunday, June 12 at 10:00 PM ET/PT on OWN.