Neil Patrick Harris has described husband David Burtka as a ''sextuple threat'' of amazing qualities in a touching anniversary message.

The loved up couple marked 15 years since their first ever date on Monday (01.04.19), and the 'How I Met Your Mother' actor gushed over his man - with whom he shares eight-year-old twins Harper and Gideon - as he called him ''the most wonderful, selfless parent''.

In a romantic Instagram post, Neil said: ''My first date with David was 15 years ago today, and we've been nearly inseparable ever since.

''I'm so, so grateful to this gorgeous man for giving me his heart, his shoulder, his strength, his lust, his laughter, his joy.

''He's an actor, chef, author, singer, producer, and the most wonderful, selfless parent I've ever seen. A sextuple threat, if you will. And I most certainly will. Happy 15th Anniversary, @dbelicious. You keep making all my dreams come true. #love''

And David - who married Neil in September 2014 - shared a sweet message of his own as he reflected on the first time they met.

He wrote on social media: ''Fifteen years ago Neil Patrick Harris and I met on the street. From that day he has made my world a better place.

''Thank you @nph for the best years of my life. I can't believe how fast 15 years have gone. Happy Anniversary! I can't wait to keep on laughing, playing and loving for years to come. #15yearchallenge #lifeisaparty''

Although the couple continue to go from strength-to-strength, David, 43, has previously revealed how didn't like his 45-year-old husband's body transformation for his role in the theatre production of 'Hedwig & The Angry Inch' in 2014.

He was forced to lose weight and get rid of his body hair for his portrayal of the title character - for which he won the Tony Award for Best Leading Actor in a Musical in the same year - but his spouse admitted it was a ''difficult time'' at home because he didn't like the change.

Speaking on SiriusXM, the 43-year-old actor said: ''I, as his husband ... I like manly guys. He had shaved his body, he had lost all this weight, he had become sort of asexual as this character ... he'd take his shirt off, I could see the bones in his back. There was no smell on him - his body was shaved, there was no hair on him, so he became this sort of androgynous being that I didn't sign up to marry.''