Celine Dion Opens Up About Husband Rene Angelil's Cancer Battle, Return to Las Vegas

The singer reveals she has to feed her husband, who has throat cancer

Dion and Angélil have been married since 1994, after meeting 14 years prior. They have three sons together -- a 14-year-old and 4-year-old twins. Dion has walked them through their father’s cancer battle.

“I really believe that children know it all,” Dion said. “We are afraid of explaining because we’re scared, because we’re worried.”

Celine Dion's Husband Stepping Down as Her Manager

Angélil, who stepped down as Dion’s manager in June because of his health, has been battling throat cancer for 15 years. Dion says it was in December 2013, just as she was about to appear on national television, that she found out her husband’s cancer had returned.

“I went back in my dressing room and I saw him looking pretty devastated, in shock, and I was like, ‘What’s going on,’” Dion recalled. “He said, ‘I have cancer again. The doctor just called me and I have cancer again.’

“At that moment, honestly, my heart started to beat faster but my body shut off,” Dion said. “So I didn’t know how to go along. He needed my support and I was like, ‘OK. I’m going to go sing. I’m going to go put makeup on and I’m going to go sing ‘Incredible’ and I’m going to forget how I feel right now.’”

“I sang the song and then reality started to strike,” she said. “It took a toll on me.”

“Sometimes [you] don’t feel what you need to feel, [you] just do it,” Dion said of that time period. “And I did and it was very hard.

“I realized I couldn’t do both,” she said.

Dion announced in August 2014 that she was canceling her Las Vegas shows and a planned tour of Asia to take care of Angélil and their sons.

Now, nearly one year later, as Angélil continues his fight against cancer, Dion says the show, and their love, will go on. Dion will return to Las Vegas on August 27 with a brand new show.

“I’m doing it for him. I’m doing it for my fans,” Dion said. “We have a ticket to live. We have a ticket to ride. We’re living, so live. Let’s go.”

The Las Vegas music landscape Dion will return to is different than the one she first saw in 2011, when she started her residency at The Colosseum, a theater built just for her show.

“I think it’s going to help all of us be the best of ourselves,” Dion said. “There’s one Mariah. There’s one Britney and it’s wonderful not only for Las Vegas.

“This is a new, wonderful opportunity for us to be able to give our best,” she said.

Watch more of Deborah Roberts' powerful interview with Celine Dion tonight on “Nightline” at 12:35 a.m. ET.