Indianapolis, Indiana - It was a big night for Lilly King in and out of the water at the US Olympic swimming trials, where she secured a second swim at the Paris Games, then got engaged.

King, the 100m breaststroke world record-holder who had already won the 100m to punch her ticket to Paris, delivered a battling final lap to finish second behind Kate Douglass in the 200m breaststroke on Thursday.

Moments later, her longtime boyfriend James Wells popped the question.

"Yes, yes!" a shocked King said after Wells sank to one knee and presented a ring, the couple hugging as cameras rolled.

"Oh gosh, I am so excited," King said as they embraced.

Later on the medal ceremony podium she showed off her ring to 20,000-plus fans at Lucas Oil Stadium in Indianapolis, in her home state of Indiana.

King will race for the US in both breaststroke events for a third straight games. She won the 100m title in Rio de Janeiro in 2016, but surrendered it in Tokyo to teammate Lydia Jacoby – who didn't qualify to defend her title.