The Backstreet Boys star has been accused of sexual assault by Melissa Schuman, 33 - who claimed earlier this month that the singer had forced her into having sex with him at his home in 2002 - but the professional dancer has praised the 'I Want It That Way' hitmaker as ''one of the most respectful'' people she has worked with on the show.
In videos posted to Twitter, Sharna - who came second with Nick on the dance contest in 2015 - described the 37-year-old pop star as ''sweet and understanding'' and admitted she was impressed by the way he always faced up to his mistakes.
She said: ''What I loved about Nick was that he always took ownership of the things that he'd been through - the darkness in his history, the mistakes that he'd made.
''He wanted to be very open about them and how he felt about them, even though they were very heavy and hard for him to say out loud, so that he could inspire other people to be better and learn from him.''
The dancer also praised the 'Burning Up' singer for being respectful and down-to-earth when dealing with everyone who worked on the competition.
She said: ''This guy would treat craft [services] and the PAs and all the crew and grips, and then the dancers to the producers -- everybody was treated the same by Nick.
''No one got more attention than the other and even in the most stressful of moments, not once did he ever speak to anybody badly, demand anything, become a diva or show anything ugly.
'' [He only showed] absolute gratitude for being there and having made it that far, and a passion for working hard and trying to do better.''
And Sharna went on to describe Nick as a ''good person'' throughout.
She said: ''This is me saying, 'Nick, I adore you. I think you are such a good person from the inside to the out, and I think that that will shine through. I think that the truth always shines through.''
But the ballroom star wanted to make it clear she was not ''victim shaming'' with her public posts.
She captioned one of the videos: ''These are only my thoughts, this is not victim shaming, y'all know me and I would never. Just because I support Nick, doesn't mean I don't support female empowerment or #metoo. They are both movements that I am a part of, here for and proud of.(sic)''
Melissa previously took to her personal blog to allege that Nick performed oral sex on her without her consent and then made her perform a reciprocal act on him before taking her to his bedroom and having sex with her without her consent.
Shortly after her blog post was published, the 'Larger Than Life' singer issued a statement in which he vehemently denied the allegations, and insisted anything that happened between them which was sexual was consensual.
Backstreet Boys: Show 'Em What You're Made Of is in cinemas nationwide for one night...