Harry Connick Jr. was terrified his wife would die when she was diagnosed with breast cancer.

The 50-year-old singer - who was just 13 when his mother passed away after suffering from ovarian cancer - did his best to hide his fears from Jill Goodacre, after she was told she had Stage 1 invasive ductal carcinoma after routine screening in October 2012, but he couldn't help but think the worst.

He told People magazine: ''I was scared I was going to lose her, absolutely.

''I wasn't going to let her see that, but I was. I know from losing my mom that the worst can happen. She's my best friend, and I really don't know what I would do without her.''

Jill, 53, found it particularly tough breaking the news to their daughters, Georgia, 21, Kate, 20, and 15-year-old Charlotte.

She admitted: ''It broke my heart.''

The former Victoria's Secret model didn't have chemotherapy, instead undergoing surgery and was left ''wiped out'' by radiotherapy.

She's also been taking Tamixofen - an oestrogen modulator pill which helps prevent the development of certain breast cancers - for the last five years and has found the side effects, which include weight gain, tough to deal with.

She said: ''I've always been a pretty fit person, and so to be just rounder and heavier and not to really be able to do much about it -- that's been hard. It's taken a lot out of my self-confidence.''

Harry added: ''It's a part of how the cancer and the treatment impacted her, and it was a real issue, even though she will always be the most beautiful woman in the world.''

Jill will come off the medication soon as she is approaching five years in remission, and she is ready to open up about her ordeal.

She explained: ''It wasn't like we were superstitious, like if we said something about being in the clear we'd somehow jinx it.

''But we wanted to be well on the other side of things before we told everybody. The doctors all say that after the five-year mark, things look optimistic, so we're starting to feel pretty good.

''It's not something that's just going to go away like it never happened. I'll always be a little nervous, always having to get checked, always hoping it doesn't come back.''