Brian Austin Green lost 20lbs after suffering bowel disease.
The 48-year-old actor - who is expecting a son with 'Dancing with the Stars' alum Sharna Burgess - has had a "rough" battle with the inflammatory bowel disease known as ulcerative colitis but explained that his girlfriend had "never experienced" anything like it.
He said: "I've dealt with ulcerative colitis a few times. It has been a real tough experience. Sharna had never experienced it at all. I've lost lost like 20 lbs."
The former '90210' star on to explain that in order to manage the disease - which causes sores to appear in the digestive tract and disrupts the normal function of the large intestine - he avoids gluten and dairy so that the body doesn't react as if it was being "poisoned."
Speaking on 'Good Morning America', he said: ""I try and avoid gluten and dairy as much as possible. It's really just dietary, like, as long as I can keep things within my system that my body doesn't think I'm poisoning it with, then it doesn't fight back. I would eat food, and literally it was like, my body didn't process any of that. So then, when you start playing catch up with, like, staying on top of being hydrated enough, that's such a battle."
Meanwhile, Sharna - who has been dating Brian since December 2020 - explained that watching her partner suffer from the disease "scared" her and that she is "still learning" about how to navigate it.
In the joint interview, she said: "It scared me. Not having experienced this type of thing before, and still learning, I was supportive and loving and [like], 'I'm here for you,' and internally fearful for how long does this go on for?"