The green open space has been a site of pilgrimage for Druids throughout the centuries, but at least one person thought otherworldly forces were at work at the nature spot this week.
An eyewitness, who recorded his name only as Andy G, made a report to the UK UFO Sightings website at 6am last Friday.
It said: “Having a break at work in the early hours on Primrose Hill, no sighting but a deep resonating humming sound coming from the near distance but unable to place the source as it came from all directions at once, but strangely from no specific direction.
“It is difficult to explain, and was witnessed by three other people at the same time.”
Camden Town Cllr Chris Naylor speculated the activity could be linked to recent revelations that a 30-metre statue inspired by the iconic Christ in Rio de Janeiro could be erected on Primrose Hill to celebrate the end of the Olympic Games.
He said: “Maybe the plans to put the Rio Christ on the hill have started to attract alien attention.
“Or maybe it’s the same PR company trying to divert attention from their Rio Christ plans.”
Primrose Hill is known for its links to paganism and spiritual activity.
The poet William Blake used the north London beacon as inspiration for his poems in remembrance of Celtic Albion.
It was on Primrose Hill, a site cherished by the early modern Druids, that the poet had a vision of the “Spiritual Sun” which he compared to the true light of the imagination.
It was also there that Blake had his vision of Celtic Albion and the divine “Jerusalem” that he predicated would rise from the capital’s ashes.
Perhaps the unexplained deep rumbling is a portent of the poet’s vision or just the true sound of imagination run wild?
Have you heard the mysterious noise around Primrose Hill? If so, contact the Ham&High news desk on 020 7433 6215.