The park was apparently "swarming" with crew and home to a "massive lighting rig" on Thursday (September 8), one member of the public told getwestlondon .
Another person working nearby also revealed that a member of the film crew had confirmed Transformers was being shot there.
Transformers: The Last Knight , starring Mark Wahlberg, Laura Haddock and Anthony Hopkins, is due to to hit cinema screens in the UK next year.
Mark Wahlberg and his co-stars have been shooting scenes for the latest addition to the film franchise in London this week, though it is not known if any of them were present at Syon Park.
A member of staff at Syon Park said an "event" was taking place there on Thursday, but said she was unable to provide any further details.
The park's website stated on Thursday that the gardens and Great Conservatory would be closed for a "private event" that day, but that Syon House itself would remain open.
Syon Park has been used as a setting for many films and TV shows, including Belle and Alice Through The Looking Glass, starring Johnny Depp.