Neil Patrick Harris has posted a touching tribute to his husband on their anniversary.

The 43-year-old actor says he met David Burtka 13 years ago, and whilst they only tied the knot in 2014, the pair - who have twins Harper and Gideon, six, together - have seen their relationship go from strength to strength for over a decade.

Posting a picture of David, 41, with their son Gideon on Instagram on Monday (03.04.17) the 'How I Met Your Mother' star wrote: ''Thirteen years and one day ago, I crossed paths with the guy on the left. The adventures have never ceased. The love has never waned. The gifts are never ending (the guy on the right, e.g.). Happy Anniversary, @dbelicious. You're the best. (sic)''

And the professional chef also took to Instagram to mark the occasion with a picture of his spouse leaning against a wall.

David captioned the snap: ''Yesterday was mine and @nph 13th year anniversary.!! Thank you Neil for being compassionate, adventurous, and an all around fantastic man. I love you more than ever. (sic)''

It isn't the first time the 'Stark Raving Mad' actor has gushed over his husband on social media either, as in 2015 he took to Instagram to dub David as ''truly wonderful'' as the pair marked their first wedding anniversary.

He wrote at the time: ''One year ago today I had the pleasure of marrying David Burtka. I'm so happy that I did - he's a truly wonderful man. Here's to many more laughs and adventures..! (sic)''

Meanwhile, David previously spoke about how ''proud'' they are to be parents.

He said: ''Just hearing their laughter, and passing on what we know and having them grow from it.

''I was really proud of myself last summer when we went to the Hamptons - we were at a toy store and the owner said, 'I've seen a lot of kids come through here and your children are the most well-behaved I've ever seen.' That gave me so much happiness to know we were doing something right.''