They have been dating since April 2004 and living together since 2007.
They split their time between Studio City, CA and New York, NY.
Burtka has twin children, born by surrogate, from a previous relationship.
Neil Patrick Harris Welcomes Twins!
How I Met Your Mother`s Neil Patrick Harris is now a father!
On Friday, the actor, 37, announced on Twitter that he and his longtime partner, David Burtka, welcomed their twins -- a boy and a girl -- Tuesday.
"Babies!!" he wrote. "On 10/12, Gideon Scott and Harper Grace entered the Burtka-Harris fold. All of us are happy, healthy, tired, and a little pukey."
He announced he and Burtka were expecting in August.
"So, get this: David and I are expecting twins this fall," he revealed on Twitter. "We`re super excited/nervous/thrilled. Hoping the press can respect our privacy..."
The same month, at the Emmys, the two-time Emmy winner told E!`s Ryan Searest, "I`m trying to read as much as I can, and prep as much as I can. But there`s only so much you can do because each baby is super individual and totally their own person ... [I`m] very, very excited. It`s the big, crazy calm before the ridiculous storm."
The babies were reportedly born with the help of a surrogate.
Sep. 8, 2014
Surprise! Neil Patrick Harris and his partner David Burtka shocked fans this weekend when they got married in a romantic Italian ceremony
Harris publicly came out as gay in 2006 and got engaged to actor and chef Burtka, 39, in September 2007. The couple has been dating since 2004. They are dads to twins Gideon and Harper, who were born via a surrogate mother in 2010.