An adorable video has emerged of Olympic gold medallist Katie Ledecky as a 16-month-old baby on NBC's Today Show.

Weather anchor Al Roker approaches Ledecky's mother in New York after spotting a 'cute baby' in the crowd and asks, 'Where is this little one from?'.

The future swimmer is wearing tiny sneakers, floral pants and a cute baseball cap, showing her sporty side even as an infant. 

Her mother Mary Gen, who once swam for the University of New Mexico, replied, 'She's from Maryland, she's 16 months', as she introduced her young children as Katie and Michael Ledecky.

The clip, filmed in 1998, surfaced after the Today Show shared it on Twitter on Monday in response to the athlete's Olympic endeavors.

Ledecky's elder brother Michael showed Roker his cuddly toy and declared: 'I have a mouse and I named him City Mouse'.

'Can we say hi to our grandparents in North Dakota? And over in Fifth Avenue we have a grandmother there that we want to say hello to,' Ledecky's mother added, as she waved her little girl's hands.

It has been a great start for Ledecky at the Rio Olympics. She crushed her world record in the 400m freestyle to win gold and jump-start a potentially historic Rio campaign on Monday.

The American star- targeting a rare 200m, 400m and 800m Olympic freestyle treble - surged home to touch the wall in 3min 56.46sec, smashing her own world record of 3:58.37 set in the Gold Coast, Queensland in 2014.

Ledecky, who has gone from strength to strength since her surprise win in the 800m free as a 15-year-old in London, has now broken 12 world records since then.

'A goal I set after Barcelona in 2013 was 3:56 or better so to see 3:56 feels really good,' said Ledecky, who beamed when she saw the time.

She had come within a whisker of the world mark in the afternoon heats, clocking 3:58.71 - the second-fastest ever until her gold medal swim.

'It felt pretty identical to this morning with a little more pop on the back half. It just felt great.'

Jazz Carlin of Great Britain won silver -- her 4:01.23 leaving her 4.77 seconds adrift. American Leah Smith took bronze in 4:01.92.