Alan Jackson and his wife, Denise, recently celebrated their 32nd wedding anniversary, and while they've spoken candidly about the marital troubles they faced -- and overcame -- in the '90s, they're just now discussing something even more trying: her bout with cancer.

In 'Backstory: Alan Jackson,' which premieres Thursday (Dec. 22) on GAC, the country superstar reveals that Denise was diagnosed with the disease last year. (Watch an exclusive preview of the show in the video player below.)

"I just couldn't believe it; it was unreal," Alan tells GAC. "To see her go through that, it was the hardest thing I've ever been through. I've been taking care of her since she was 16, but I couldn't do anything to help her. It was tough."

"Once you get that phone call and you hear that word 'cancer' ... I will never live another day in my life and expect anything," says Denise. "I will get up every day and be grateful for my health and the health of my family."

Denise is the author of the inspirational memoir, 'It's All About Him: Finding the Love of My Life.' Mom to the couple's three daughters, Mattie, Ali and Dani (pictured above), she insists many blessings came with her illness.

"For my children to see my faith in a situation like this, I think it made a profound impact on them," she says.

The 'Backstory' episode also centers on Alan's remarkable music career. Since emerging in 1989, the same year that saw the debuts of Garth Brooks and Clint Black, among others, Alan has scored 35 No. 1 hits.

"It's great to see an artist like Alan Jackson who knows who he is, who doesn't waver based on what's going on," says admirer Lee Ann Womack. "He just keeps being Alan."

'Backstory: Alan Jackson' premieres at 10:00 PM ET this Thursday, Dec. 22, on GAC. Be sure to tune in for an important update on Denise's progress in her cancer battle.

Watch a Preview of GAC's 'Backstory: Alan Jackson'

if(typeof AOLVP_cfg==='undefined')AOLVP_cfg=[];AOLVP_cfg.push({id:'AOLVP_us_1338099774001','codever':0.1,'autoload':false,'autoplay':false,'playerid':'61371447001','videoid':'1338099774001','publisherid':1612833736,'playertype':'pageload','width':476,'height':357,'videotitle':'Test','bgcolor':''});