Serena Williams was caught on camera being told to put away her phone for trying to take pictures of Tiger Woods at the Honda Classic.
The world number one tennis player was following the 14-time major winner in Florida but didn't realise that under PGA rules, spectators are not allowed to photograph or video players during competition.
"Apparently you can't take pictures of golfers," tweeted Williams. "In my defence [people] always take pics of tennis players."
Williams is the current Wimbledon and US Open champion.