Adam Peaty's record-breaking golden swim at Rio 2016 was greeted by screams of delight - and a series of tweets - at his nan's Staffordshire bungalow home.
Internet sensation Mavis Williams had stayed up late to see her grandson make history in the 100m breaststroke final.
The self-proclaimed #OlympicNan - who has gained more than 3,500 followers on Twitter - joined tweeting British sports fans across the nation in remaining #UpAtThreeForAdamPeaty.
She quickly shared her delight at him becoming Team GB's first gold medal winner of this Olympics.
She later told ITV News that her Olympic champion grandson's achievements were even more remarkable given he grew up scared of water and refused to be taken by his family to the swimming pool.
Despite a lack of sleep, the 74-year-old continued the celebrations with a garden party at her home in Uttoxeter.
Peaty told reporters over in Brazil that he "can't wait" to come home and see his most famous fan, who he refers to as a "classic" nan.
Mavis, who painted her nails in the GB colours for his Olympic effort, revealed how she will greet him.
"I'll give him a hug and tell him I'm as proud as punch," she said.
Mavis earlier told ITV's Good Morning Britain of her reaction as he completed his world record swim.
"I went ballistic," she said. "(I was) very pleased for him because he's worked so hard for it."
Although she said she "knew he'd do it", she admitted the tension got the better of her in the build up to the final.
"I just put my hands in front of my eyes until he left that block," she said.