The TV presenter, who presents the ITV daytime show alongside Holly Willoughby, took to social media to reveal the news this morning.
Phillip and Holly usually have Fridays off but the pals opened today's edition of the ITV show with a special interview to discuss Phil's announcement.
Speaking to Holly, an emotional Phillip said: "It's funny because everyone i've spoken to, including you, has been so supportive and so loving and caring.
"My entire family have and said it's ok, I love you.
"Every person I tell it gets a little easier."
"I am very aware Steph and the girls are watching this. We've spent a lot of time together."
In his lengthy statement, Phil revealed that he is splitting from his wife Stephanie Lowe after 27 years.
Presenter Holly asked her friend: "Why now?"
Phillip responded: "This has been bothering me for a long time. No question it has in recent times consumed my head.
"It has been an issue in my head. I got to the stage where we sit hear everyday, and I am over there, and some crazily brave person shares their story with us.
"I'm like 'Oh my god you're so brave.' and I have to be that person."
Talking about wife Steph: "I am very aware this causes upset and pain.
"I've had to deal with this for some.
"No one in my life has supported me like she has. She is astonishing."
Phillip continued: "I feel guilt but I am proud of being here today.
"I couldn't not have done it without you, Holly You're the sister I never had."
Holly told her telly husband that she will be by his side forever and ever and the pair ended their emotional chat with a massive hug.
This Morning airs weekdays at 10am on ITV