The couple – who met in 1995 – released a statement confirming the news, insisting their main focus is their three children.
It read: "While the two of us have come to the mutual decision that we will no longer be partners in marriage, we remain partners in parenthood and are committed to jointly raising our three sons in a happy and healthy environment."
According to reports, Gwen, 45, filed for divorce from 49-year-old Gavin, citing 'irreconcilable differences'.
It is believed that both of them have also filed for joint custody of their boys Kingston, nine, Zuma, six, and 17-month-old Apollo.
Gwen and Gavin are allegedly both asking for joint custody of the children, while she is said to be refusing to grant him spousal support.
No Doubt singer Gwen is worth an estimated $80 million, while Gavin is worth a reported $35 million.
In March this year Gwen discussed her marriage to Gavin, suggesting that they both enjoyed having time apart from each other.
She told Cosmopolitan: "We go through so much together – it's a miracle that we could stay together this long… It's good to have those days when we both do our own things.
"I think that's what keeps relationships going, when both people can be themselves and have their own individuality."