Tom Dean claimed a stunning gold and Duncan Scott silver to ensure a British one-two in a thrilling 200m freestyle at the Tokyo Olympics.
In a fast, closely-fought final, Dean touched home just ahead of world number one Scott on his debut Games.
Scott finished just 0.04secs behind his team-mate, with Fernando Scheffer of Brazil taking bronze.
It is the first time since 1908 that two male British swimmers have finished on the Olympic podium together.
The two Britons high-fived before sharing a hug as their remarkable podium finishes were confirmed.
Both swimmers looked shocked as they spoke to BBC Sport afterwards, with Scott describing it as an "unbelievable moment".
Scott, who qualified fastest, was the favourite going into the race but Dean was able to back up his rapid start with a strong finish.
His winning time of one minute 44.22secs is a British record.
The 21-year-old had a difficult build-up to Tokyo after twice contracting coronavirus in 2020, which kept him out of the pool for three weeks on each occasion.
Despite the disruption, he arrived at the Games as the second fastest man in the year, behind Scott.
"I knew it was going to be a dog fight," Dean told BBC Sport.
"I didn't know how people were going to swim it. It was just race to race.
"Thanks so much to everyone back home - my mum, my family, my girlfriend. All the boys back in Maidenhead - thank you for staying up."
Scott, who won European silver in May, said he was "just buzzing for Deano" as the two good friends allowed their victory to sink in.
The British team - including Adam Peaty, who won a historic 100m breastroke gold on Monday - cheered the two on from the stands, with several reduced to tears by the emotion of the moment.
"You can't describe that, when you have worked so hard, to share this medal moment with one of your best friends is an unbelievable feeling," two-time Olympic gold medallist Rebecca Adlington told BBC TV.
"Duncan will be slightly disappointed because he was the fastest and the favourite but, at the end of the day, you can tell that if anyone were to beat him, he would want it to be his team-mate."
It is the first time since 1908 that two British male swimmers have shared an Olympic podium
Duncan Scott and Tom Dean will compete together in the 4x200m freestyle relay later in the weekScott was quick to praise Dean, with the two celebrating together on the podium as they received their Olympic medals.
"He has come on so far in the last 18 months and it is a pleasure to watch," Scott added.
"He is a good made out of the pool and it is great to be able to compete against him."
Dean's triumph ensured Britain won their fourth gold medal of the games after Peaty, Tim Pidcock and Tom Daly and Matty Lee's successes on 'Magic Monday'.
Elsewhere, Britain's Kathleen Dawson finished sixth in the 100m backstroke, while Freya Anderson missed out on qualifying for the 200m freestyle.
