PHOTO: Steve Granitz/WireImage
The former couple, who were married for two years, walked the red carpet together, posing for photos with their arms around each other's waists.
Lavigne posted additional photos on her Instagram that show the two as all smiles. "Grammy Party ..... Feeling great. Lovely night," she captioned one shot of her and Kroeger.
When the two separated back in September, Lavigne wrote on Instagram that she and Kroeger "are still, and forever will be, the best of friends," and since that announcement the two have stayed true to those words.
As Peoplereported, the two have written songs together since their breakup and were last seen leaving a hotel together in December.
Neither has commented on the current status of their relationship.
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