Super-fun day in the Harris-Burtka household!

Neil Patrick Harris and fiance David Burtka celebrated the first birthday of twins Gideon Scott and Harper Grace on Wednesday.

"Things I dig: our twins Gideon and Harper, who are one year old today!" How I Met Your Mother star Harris, 38, Tweeted. "They are glorious. So proud to be their Papa."

Harris gushed of love Burtka: "And I'm in awe of, and so grateful for, David Burtka. He is, in my humble opinion, the greatest dad in the history of ever."

Son Gideon and daughter Harper may be wearing baby formalwear soon enough: Their proud papas confirmed long-held plans to marry in June, right after gay marriage was legalized in New York State.

"David and I did propose to each other, but over five years ago!" Harris explained. "We've been wearing engagement rings for ages, waiting for an available date."