Josh O'Connor is an English actor whose career runs from British television drama to leading roles in international films. His connection to UFOs comes from one part: Dr. Daniel Kellner, a cybersecurity specialist and whistleblower, in Steven Spielberg's 2026 science-fiction thriller Disclosure Day, and from the interviews he gave while promoting it.

Born Joshua Mathias O'Connor on May 20, 1990, in Southampton, he graduated from the Bristol Old Vic Theatre School in 2011. He played Larry Durrell in ITV's The Durrells from 2016 to 2019 and had his breakthrough in 2017 as Johnny Saxby, a young sheep farmer, in Francis Lee's God's Own Country, which won him a British Independent Film Award. His portrayal of Charles, Prince of Wales, in the third and fourth seasons of Netflix's The Crown brought him the 2021 Primetime Emmy for outstanding lead actor in a drama series and the Golden Globe for best actor in a television drama.

His film work since then has included Emma in 2020, La chimera in 2023 and the tennis drama Challengers in 2024. In 2025 he appeared in The Mastermind, The History of Sound opposite Paul Mescal, and Rian Johnson's Knives Out mystery Wake Up Dead Man, in which he played a priest. In November 2024 he was reported to have joined Spielberg's then-untitled film as the co-star of Emily Blunt.

Disclosure Day, written by David Koepp from Spielberg's story, opened in the United States on June 12, 2026, and earned about $241 million worldwide by early August. O'Connor's Kellner steals alien technology and "the Archive," decades of footage and documents, from the secretive contractor Wardex, then flees with Blunt's Kansas City meteorologist, Margaret Fairchild, to make the material public; the film reveals that the two were abducted together as children. Wardex is run by Colin Firth's character, and Colman Domingo plays its defecting director of biological assets. The March 2026 trailer gave Kellner a line about people's right to know the truth, which journalist Ross Coulthart quoted approvingly on X.

On the press tour O'Connor and Blunt told Extra that they did not believe humanity was alone and that the possibility excited them, and clips of their remarks circulated widely on UFO accounts. The film made O'Connor, an Emmy winner known mainly for character-driven drama, the screen face of the whistleblower in the most widely seen disclosure story of 2026.