An unflustered Walker desperately held back laughter as he became aware of the nocturnal activities taking place in the background.
He then tried to reassure viewers that the bizarre scene wasn't "that" and that the pair were 'having a hug' or 'reading a book.... in a strange pose'.
To the disappointment of some viewers, Walker also informed viewers his camera team were not going to zoom in on the non-sporting action.
Disbelieving viewers quickly took to Twitter to describe what they'd just seen.
One wrote: "Is it just me or has the BBC started broadcasting sex on the beach? #BBCOlympics"
Another added: "Best action I've seen all Olympics! #BBCOlympics"