Harding was on hand at London’s Music Industry Trust Awards with an engagement ring on her finger.
She presented an award with the other members of her group, including Cheryl Cole, Kimberley Stewart and Nicola Roberts. Nadine Coyle was not in attendance.
A friend close to Harding and Crane said that the two are planning to have a rock and roll wedding ceremony.
Harding previously mentioned that her relationship with Crane was stronger than ever before, and that she wanted to marry him and start a family.