A cute video has emerged of a two-year-old girl hearing her baby sister's heartbeat for the first time.

The footage, shot on April 11 in Massachusetts, USA, shows Madilyn Jeanne Smith holding the foetal heart monitor and listening her sister Olivia Marie's heart in her mother's belly.

"As you can see by her smile, Madilyn was very happy to hear her little sister's strong healthy heartbeat," the mother wrote online.

"Since the day Olivia has arrived Madilyn has been in awe of her," she added.

Two year old Madilyn Jeanne Smith had been anxiously awaiting the arrival of her baby sister, Olivia Marie. I brought Madilyn to one of my prenatal checkups and our doctor was quite delighted to let Madilyn help check on her baby sister. After healoing to measure my stomach, our doctor allowed Madilyn to hold the fetal heart monitor and listen for a heart beat. As you can see by her smile, Madilyn was very happy to hear her little sister's strong healthy heartbeat. We watched the video often in anticipation of Olivia's arrival. Since the day Olivia has arrived Madilyn has been in awe of her. You can view more of Madilyn's excitement of her baby sister at https://www.youtube.com/channel/UC-buIHdqF_7_aCZYJq8zMig