The couple announced the end of their seven-year marriage today (23.01.12) shocking the showbiz world and those close to the pair are equally as surprised by the news.
Niche Media founder Jason Binn - who has been friends with the supermodel for over 20 years - told People: "All this is just shocking to me. I've only seen them as the most loving couple."
A fashion industry source who has worked with Heidi - who is believed to have ended the relationship months ago - is equally as shocked by the separation, saying: "The Heidi and Seal I knew was the couple everyone loves, super passionate and in love."
Seal, 48, and Heidi, 38, claimed in a statement they were ending their union after growing apart but insisted they still "love each other very much".
Despite their statement, pals are now speculating about what could have happened between the pair - who raise four children, Leni, seven, Henry, six, Johan, five, and two-year-old Lou, together - to have caused the break-up.
A friend of Heidi's said: "It has to be something major. They have four kids together, and they've always been very committed to making it work."