Star Wars actor Ben Mendelsohn and Cobie Smulders, who played Robin in How I Met Your Mother, were spotted outside The Piece Hall in Halifax yesterday.
As our video shows, extras in costumes were also seen headed into the building.
As reported by the Courier, there was much excitement on Monday when Samuel L Jackson was seen in Halifax.
He popped into Pride and Provenance for lunch and, later, was seen again leaving The Piece Hall.
The historic venue has been shut for a week and transformed into a film set for the making of the six-part Marvel show, which will be screened on Disney Plus.
Other cast members are thought to include Kingsley Ben-Adir, Olivia Colman, Emilia Clarke, Killian Scott, Christopher McDonald and Carmen Ejogo.
There is still plenty of activity around The Piece Hall today, with people carrying set and filming equipment into the historic building, a huge light positioned overhead, and lots of trucks and other vehicles parked up.
Eureka! has announced it will be shut until Friday because of the Marvel filming. Crew vehicles are parked up in the museum's car park.
Marvel are also thought to be filming at Dean Clough. Vehicles to be featured in the show have been seen parked up and West Yorkshire Fire Service has warned there could be theatrical smoke in Old Lane and Dean Clough between 11.30am and 11.30pm tomorrow.
See our video and pictures as filming started at The Piece Hall yesterday HERE