This heartwarming video shows preschoolers at an American school starting their day with a smile by greeting each other in fun ways.

Every morning at the Lone Tree Elementary in Lone Tree, Iowa, pupils line-up and then choose a greeting from a chart a hug, handshake, or a fist bump.

Next the classes' nominated morning greeter will give them the greeting they desire.

The children's teacher Kali Lovgren set up the cheery morning activity to encourage positive interactions between students.

Kali, who shared the adorable video on social media, said: 'The preschoolers love greeting their friends in the morning. They seem to look forward to that time, and I have caught them role-playing that part of our school day in the afternoon.

'The aim behind the greeting is for students to have a positive interaction with their classmates right away in the morning.

'I also wanted them to have a choice, because students always enjoy an activity or routine more if they have a choice in it.

'We have our greeting time every morning. The person who is the greeter changes each week on our job chart.

'I found a document on Teachers Pay Teachers [website for education resources] created by The Core Coaches and decided to give it a try.

Every morning at the Lone Tree Elementary in Lone Tree, Iowa, pupils line-up and then choose a greeting from a chart a hug, handshake, or a fist bump. These two adorable pair are seen fist-bumping each other

The children's teacher Kali Lovgren set up the cheery morning activity to encourage positive interactions between students. The picture shows two little boys high-fiving each other

The classes' nominated morning greeter will give them the greeting they desire. The picture shows two preschoolers enjoying a hug

In the clip, a little boy in a white t-shirt stands ready and waiting with the colored greeting chart for each of his classmates to pick their greeting.

Some already have their greeting picked while others take a second to choose, but every child has a huge smile on their face as they are welcomed into the classroom.

Kali added: 'The students loved it so much I decided to have them do it to say good bye as well, and each day I draw a name to be the See You Later Alligator.

'I decided to record them one morning so that their parents could watch it. I showed it to our secretary and she wanted to share it with the community, it has been a hit ever since.

'We have had a very positive reaction to the video and I've had many comments from our school board, staff, parents, friends and family not only about how cute it is but also about the positive message it is sending our students.

'Because of this interaction with their classmates, each child has been starting their day off with a smile and that is an amazing thing to see.'