See Shania Twain Mentor 'Voice' Singers, Jesse Larson's Adele Cover

Plus, TSoul covers a Willie Nelson classic and Brennley Brown takes on Linda Ronstadt

Shania Twain surprises 'Voice' hopefuls as the season's key adviser.

"That Don't Impress Me Much"-referencing jokes and stupefied looks abounded last night as contestants on Season 12 of The Voice met key adviser Shania Twain. In the video above, the show's hopefuls meet the country icon. Fittingly for the Twain, some of the most promising artists for Season 12 of NBC's The Voice are country acts, and last night's two-hour live playoff episode certainly brought the genre to the forefront.

Perhaps unmatched vocally this season, powerhouse singer Jesse Larson dazzled the audience and judges alike with his stirring rendition of Bob Dylan's "Make You Feel My Love," notably recorded by Garth Brooks and again by Adele on her 2008 debut 19. With Larson garnering comparisons to former Voice coach CeeLo Green, his coach Adam Levine praised his latest performance. "You're the best pure singer in this competition," he said.

Another contestant who showed some savvy with country material was Team Blake member TSoul, who took on Willie Nelson's 1982 hit "Always on My Mind" (also recorded by Brenda Lee, Elvis Presley, and the Pet Shop Boys). Staying true to Nelson's arrangement, TSoul's soothing vocals and flashy runs showed some versatility, considering he's mostly stuck with soul and blues tunes until last night. Shelton was pleased. "I never saw anybody who gets lost in their performance like you do. I love that as an artist and a fan," he said to TSoul.

One of the crowd favorites, 15-year-old Brennley Brown, covered Linda Ronstadt's 1971 Grammy-nominated single "Long, Long Time." During rehearsal, Brown admitted to coach Gwen Stefani and Shania Twain she'd like to cover the song on her own album one day. Stefani urged Brown to steer clear of trickery since her voice is so remarkable. Twain backed her up, adding, "People will always be impressed with power notes. You need to do what's true to you."

Brown started subdued and seated, soon revealing a lower, sultrier side of her voice and gradually gaining momentum as she confidently crossed the stage. She concluded with an airy falsetto, seeming comfortable with a love ballad that stretches beyond the type of yearning most high school sophomores know.

The coaches and Twain seemed in awe of another strong Brown performance. "I don't know what to say, this really is as good as it gets no matter what age you are," said Twain. Stefani agreed. " I feel like I spend my whole life thinking about you these days, all day long listening to country music trying to find the right song and that was perfect," she said.

Blake Shelton's team member Lauren Duski also had another noteworthy performance. A fitting song for her rich, layered voice, Duski performed "Lord, I Hope this Day Is Good," written by Dave Hanner. Made popular by Don Williams in 1981 and Lee Ann Womack in 2000.

"You have an honest spirit. And this song you could have written, and I felt that," said Twain. Duski's coach Shelton pleaded with voters. "Listen to me America. Country music fans," he said. "This girl is the artist we've been waiting for on this show. All this girl needs is a microphone and a country song and she lights the place up."

Also of note last night, Lilli Passero performed Shania Twain's 1999 smash "Man, I Feel Like a Woman." Despite being sick enough to miss rehearsal, Passero powered through it animatedly. Another contestant to watch is the soulful Troy Ramey, who put a soulful, Dobro-driven spin on Tom Petty's 1989 hit "Free Fallin'."

The Voice live playoffs return tonight, April 25th at 8:00 p.m. ET on NBC.