THE world's happiest lizard has become an internet celebrity with thousands of followers - because he can't stop smiling.

Smaug the smiley mini dragon has almost 4,000 followers on photo-sharing app Instagram, making him Britain's most famous reptile.

Unlike his miserable namesake from The Hobbit, the chuffed creature loves walking around the house, playing in the garden and even making trips to Pets at Home.

Charlotte Birch, 22, rescued four-year-old bearded dragon Smaug in November 2015 after his previous owners weren't caring for him properly.

Charlotte, from Taunton, paid £80 for the cute reptile, who was being kept in a cold garage without much human contact.

He has metabolic bone disease because of a lack of proper lighting, leaving him at half the size he should be.

But Charlotte says he is one of the loveliest pets she's ever had, despite his special needs.

She said: "I rescued him from his old owners who kept him in a garage.

"He has metabolic bone disease because he wasn't given proper lighting, so his growth is stunted and he's not as long as he should be, and I have to hand-feed him because of his special needs.

"He's one of the loveliest pets I've ever had though, he taps on the glass to come out of his cage and he loves walking around the house and snuggling.

"He's actually started venturing out into the garden, even though bearded dragons tend to be scared to go outside because of the birds, but he just walks outside and sits there on his own.

"I took him to Pets at Home and he really liked it, he just sat on my shoulder looking around at things.

"His smile comes from him trying to regulate his temperature - it's like a dog panting - but because of the shape of his mouth, it looks like he's smiling all the time."

Charlotte says her friends suggested the Instagram account - but Smaug now has more followers than all of them, herself included.

The adorable lizard has 3,800 followers, and regularly gets more than 300 likes on his pictures.

Charlotte is now planning to sell merchandise adorned with Smaug's face, and says she will donate part of the proceeds to animal rescue centres.

She added: "I had a few friends who knew about him and they said I should set up the account.

"He's so cute and sweet and he does funny things because he's so clumsy, so I thought I'd give it a go.

"I set it up at the end of January and got 1,000 followers within a few weeks, it's now up to 3,700.

"I wasn't expecting it at all. I thought maybe he'd get 100 but there are lots of reptile accounts on Instagram."

"My friends who suggested it are really surprised - they don't have that many followers.

"I only have about 150 followers so he has way more than me."