The couple, who began dating when they met in late 2004, became engaged in November 2007 while on holiday in Bali.
An official statement read: "Delta Goodrem and Brian McFadden regretfully announce that they are no longer engaged, and after much consideration, have mutually decided to end their relationship.
"This decision has been made with a lot of soul searching from both parties with the realisation that they have grown apart. They leave the partnership with respect for one and other, wishing each other success and happiness for the future."
It concluded: "Delta and Brian appreciate there will be interest regarding this announcement but request that their time together is respected and they are given privacy during this time of transition."
Writing on Twitter, McFadden added: "I love delta and always will. She is one of gods living angels. I thank her for giving me the best years of my life. Please give us time (sic)."
In 2005, the pair scored a UK top three hit with their duet 'Almost Here'.
> Brian McFadden throws "hissy fit"
Watch the video for Brian and Delta's single 'Almost Here' below: