Ashlee Simpson Breaks Down While Discussing Cancer Update With Dad Joe

Ashlee Simpson couldn't hold her tears back as she and father Joe Simpson recalled his serious battle with cancer.

In a sneak peek of Sunday's episode of Ashlee and Evan, Joe — who was diagnosed with prostate cancer, as first reported in November 2016 — is seen giving an update to his daughter about how he's been doing.

"The biggest part is because I don't have testosterone I just don't have energy," he said in the video, as first reported by Us Weekly. "So you have to power through."

The fashion photographer then discussed how he almost didn't go through with getting treatment following his diagnosis.

"A year ago changed my life," Joe said. "I remember saying to the doctor, 'What if I don't have surgery?' And he said, 'In six months, you'll be dead.' You know, I really wrestled with just saying, 'I'll see you guys later.'"

After that statement, Simpson can be seen holding back her tears telling her dad: "Definitely not that time. I am not ready for that."

"I couldn't do that to you and to your sister [Jessica Simpson] and to my little grandbabies," Joe said, adding his family was the reason he chose to fight his disease.

Joe is the grandfather of Jessica's children with husband Eric Johnson, Maxwell, 6, and ace, 5,. Jessica is also expecting baby no. 3, as she announced earlier this week.

Joe is also grandfather to to Simpson's kids, Bronx, 9, and Jagger, with ex-husband Pete Wentz and husband Evan Ross, respectively.

"We definitely couldn't do that either," Simpson said, adding, "You're so strong, and I'm just so happy you're here."

Joe replied: "I'm not really strong. I'm just a good liar."

According to Us Weekly, Joe first underwent surgery for his cancer treatment in September 2016. He also begun radiation treatment in February 2017.

Simpson made headlines in early September for giving fans an update on her father's condition.

"It's such a blessing," the "Pieces of Me" singer told E! News of her dad's recovery in a new interview. "He's doing good now and feeling good. I'm so happy he's healthy now."

At the time, Ross also celebrated his father-in-law's better health, reflecting on how much the experience affected his family.

"It was a really scary experience for Simpson, for their whole family," Ross added. "So for me I was just trying to make sure I was there and paying attention to how everyone was feeling."

Watch all new episodes of Ashlee and Evan Sundays at 10 p.m. ET on E!