The 26-year-old and his fiancee Lisa Stelly welcomed baby Pearl to their family in April and Jack said he is concentrating on his duties as a parent rather than dwelling on his condition after the diagnosis in May, reported Contactmusic.
"When you get news like MS, it's a bit of a buzzkill. But having a baby is forcing me to focus on just that and my work, so it takes the sting away a little bit," he said.
Jack said his mood is lifted as he sees how quickly his baby girl is growing.
"She recently rolled over for the first time. We're excited about it because she's so advanced. Most kids don't do it until 14 weeks. Expect big things."