A representative for the swimmer said his thoughts were with Ryan's family, as per the Daily Mail.
“Everyone is distraught,” a different source told The Daily Telegraph. “It is just so sad and everyone is shocked.”
Eight weeks ago, Ryan shared a picture from Sydney's St Vincent hospital with the caption "Covid got me GEWD" after testing positive to the virus. At this stage, it is not clear whether the virus had anything to do with his death.
Ryan was Ian's first long-term boyfriend after the Olympic swimmer came out as gay.
They were on-and-off again before eventually breaking up for good in 2019.
While dating, Ian and Ryan considered having a child together via surrogate.
WATCH: Ian Thorpe reveals he's excited to start a family (Article continues after video)
After being spotted at a LA reproductive clinic in 2019, the swimmer confirmed to the Daily Mail that he and Ryan planned to expand their family.
“We’re talking about it and have for a while, but it’s still early days," Ian said.
"We decided to visit the clinic in LA - it's all part of the plan at this stage."