Ian Somerhalder "couldn't be happier" after two years of marriage to Nikki Reed.

Nikki Reed and Ian Somerhalder

Nikki Reed and Ian Somerhalder

The 38-year-old actor tied the knot with Nikki, 28, on April 26 in 2015, and he has taken to Instagram to pay a glowing tribute to his wife, hailing her as the "talented woman I've ever known".

Alongside a photograph of the couple on their wedding day, Ian wrote: "To the most amazing human in the world. Thank you for 2 incredible years of marriage. Today, two years ago to the minute, we said "I do" and I couldn't be happier or more grateful to you for this life. Thank you for being my best friend the hardest-working, kindest, most patient and most talented woman I've ever known. To you my love, I say that I know we will have so many of these we can't even count them. Partly because I'll be so old... I love you (sic)"

Nikki has returned the compliment, taking to her own Instagram account to pay tribute to Ian.

The actress said her husband is her "better half in every way".

Alongside a black and white snap of the couple on their wedding day, Nikki wrote on the photo-sharing website: "My guy, my man, my honey, my partner in this life, my better half in every way. At exactly this time two years ago today we walked hand in hand into the next chapter, our chapter, together. Every day gets better, every moment calling for even more. Navigating the waters of life with you is the greatest and most rewarding adventure I've ever known. We climb, we grow, and we laugh at all of it. Thank you for being exactly who you are, and for loving all of me. Thank you for your willingness to go even deeper. Until you, I had no idea what could be. Until you...Happy Anniversary (sic)"