ITV switched off all of its seven channels for an hour on Saturday as part of a national sports day event called I Am Team GB.
People from across the UK were encouraged by ITV and The National Lottery to get out and active by taking part from 9.30am.
Double Olympic gold medal-winning gymnast Matt Whitlock appeared at the end of Aled Jones' Weekend show to urge viewers to get involved in the event.
He was then seen pulling a lever to switch off all ITV channels just before programming stopped.
Some members of the show's production team also got involved.
One viewer revealed he was going for a run, writing on Twitter: "Great and brave idea #ITV, one day I won't be able to #run but today isn't that day!"
Another revealed she had just been for a "45-minute spin class".