Neil Patrick Harris leaves fans speechless over same detail after seeing rare new photo of twins

Neil Patrick Harris and his husband his husband David Burtka have got all their fans saying the same thing as they shared a rare photo of their daughter last week.

For those who need a reminder, the How I Met Your Mother actor, 52, married David, 50, back in 2014 after first going public with their relationship all the way back in 2007.

Then, in 2010, Neil and David became parents to twins Gideon and Harper, who are 15 years old, after a surrogate carried and gave birth to them.

Since then, the celebrity couple have shared rare glimpses of the twins on social media as they've grown up - and their followers have been left shocked by just how quick time is flying and they're growing up.

David attended the Wicked: For Good New York premiere which was held at the Lincoln Center for the Performing Arts on November 17 and took along Harper as his plus one. The perks of having famous dads!

Neil Patrick Harris and husband David Burtka welcomed their twins via surrogate back in 2010 (Bruce Glikas/Getty Images)

The two were papped on the red carpet, with the father-of-two looking dapper as he sported a metallic bronze suit jacket, white shirt and black trousers.

Meanwhile, Harper looked glamorous in a light green sequinned dress and black fur coat, as they stood together for snaps.

David shared an Instagram post of the evening which also included a video of the elaborate venue as they took their seats to watch the highly-anticipated movie, with the cast, including Ariana Grande, Cynthia Erivo and Jonathan Bailey also making an appearance at the star-studded event before the film began.

David wrote in his caption: "I had the best time at the most over the top premiere Monday night @wickedmovie and @lincolncenter. I’d tag my gorgeous date but she still doesn’t have instagram."

He emotionally added: "It’s hard to believe she is 15 years old. I am so proud of her, she is a dynamic kid #grateful."

The dad went on to disclose that for anyone wondering, her dress is from the brand Alice and Olivia and her coat is from Lanvin.

As we say, the comments were flooded with fans expressing their shock at how they also can't believe that Harper's already fifteen.

The father-daughter duo attended the Wicked: For Good premiere last week in New York (Dimitrios Kambouris/Getty Images)

One Instagram user penned: "Your daughter is growing up to be a beautiful, classy woman. Be proud papas."

While a second agreed: "You guys are lovely. I remember when she wasn't still one year old and smiled for the Easter picture with bunny ears next to the sibling."

And a third speechless fan added: "FIFTEEN???? Where does the time go, I could swear you two just had those babies yesterday!"

Others chimed in with: "My God, how much time has passed from yesterday to today?" and "How she's grown, just like when you and NPH started getting famous in the late 80s and early 90s."

Another quipped: "How??? She was just a baby" while someone else added: "I simply cannot with Harper all grown up. I refuse to accept this."

"Sir, she was just 4!!! When did this happen?" questioned another social media user, while someone else wrote: "How are the twins 15 already. Insane."