Somerhalder's rep has declined HuffPost's request for comment.
The pair, who became an item shortly after Reed's divorce from Paul McDonald and Somerhalder's split from longtime girlfriend Nina Dobrev, were friends before sparking up a romantic relationship. The 26-year-old actress and McDonald called it quits last spring, after almost three years of marriage. Their divorce was finalized earlier this month.
Somerhalder recently shared a photo of his reported fiancee on Instagram, calling her "incredible":
No filter for this sunny Sun Valley day of awesomeness with my loves, the incredible @iamnikkireed and my brother @nathanaugustreed .The Happiest of holidays to everyone, may nothing but smiles, family time and reflection come from these moments. I'm grateful for all of the love this years for me, us and ISF from everyone-may you empower all around you with the same strength and energy you have to spread positivity and compassion. Smiles are contagious-please spread them;) I'm grateful for and l love you all... Love, Ian