World's cutest grandad: '87 years young and he's my number one guy'

An adorable video of an elderly man's reactions to his granddaughter's visits has gone viral.

Jennifer Barclay, from Scotland, posted the video to Twitter on Friday, sharing the compilation clip of her 87-year-old grandfather "Robert" greeting her at his front door as she arrives for dinner on numerous occasions.

In the sweet clip, Robert beams every time he opens the door, even playing jokes on his granddaughter, asking her to give him "the password", before embracing her in a hug.

Captioning the video, Jennifer wrote: "My wee Grandad, 87 years young and he's my number one guy.

"I love him with all my heart. And I love recording his reactions when I come to visit. I hope everyone can appreciate the video I've made as much as I do".

It didn't take long for the video to go viral, seeing over 82,000 retweets and 445,000 likes from followers and strangers alike who shared their adoration of the pair's heartwarming relationship.

At the end of the clip, her grandad opens the door with a big smile on his face, saying: "Hello honey bun" and melting hearts across the internet.

In a second tweet, Jennifer shared: "No matter how many times I watch the video of my granddad opening the door, it brings a tear to my eye. So much love".

The video has had over five million views in three days, as well as thousands of commenters sharing their own stories.

One follower wrote of her own video: "Reminds me of my grandfather. I got this video of him when he made me soup at 6 in the morning after hearing from my mom I was sick."

Another added: "My grandfather died when I was 12. I always wish I could have had more time with him; he was a wonderful man. I cherish the memories I do have (including all of those Italian Sunday dinners!) a great deal."

Another shared his recent story of loss: "I lost my Grandfather this week. He was 90. A second father to me... I'm gutted, but will always remember his kindness, teasing and unconditional love."

Many users admitted the video brought out their emotional side, and praised the post.

"What I would do for one more visit with my own. This just made my heart so full", one wrote.

Another tweeted: "What a gem, grandparents are the best. I wish I still had mine".

While another concluded: "If someone isn't this happy when they see me, then I don't need them".

Jennifer then went on to joke that her grandfather had "broken the internet" and has set up an Instagram account for those wanting to see more of the sweet man.

The account, named the.grandad.diaries has so far only shared one post, but has already gained over 1200 followers.