As scenes from the new superhero blockbuster Avengers: Age of Ultron were filmed in Norwich, Robert Downey Jr - who plays Iron Man - took time to chat to a Norfolk toddler about his pyjamas.

Part of the University of East Anglia campus was turned into a 'secret' movie location for the follow up to the box office hit Avengers Assemble.

Robert Downey Jr flew in by helicopter, while the campus was awash with apparent sightings of other stars, such as Chris Hemsworth (Thor) and Chris Evans (Captain America).

Sarah Gray, who works at the Norfolk and Norwich University Hospital, was lucky enough to meet Downey Jr, when his helicopter took off from near the hospital on Friday afternoon.

Mrs Gray, who lives at Blickling, said: 'He was an absolute gent. He saw us standing, he could have gotten straight into the helicopter. Instead he came over and chatted.'

The Hollywood star shook hands with a little boy called Lewis Olsen, three, who was wearing pyjamas, and asked him about his attire.

Lewis's dad Nick, from Dereham, said: 'I'd just dropped my wife off for her night shift at the hospital and Lewis had wanted to see the helicopter.

'He didn't know who he was meeting. When I got home I went on Google to show him that he'd just met Iron Man.'

The large 'A' sign for the Avengers could be clearly seen on the Sainsbury Centre's Modern Life Café which had four high performance cars positioned outside.

A giant green screen was also put up next to the building and groups of actors dressed in blue outfits - thought to be playing Avengers recruits - were repeatedly filmed running backwards and forwards in front of the screen. Later in the day people claimed on Twitter they had seen Aaron Taylor-Johnson (Quicksilver) and Elizabeth Olsen (Scarlet Witch).

Hollywood A-listers Scarlett Johansson and Samuel L Jackson are among others in the Avengers: Age of Ultron cast. The Marvel Studios film – due for release next year – is directed by Joss Whedon, who also helmed the first Avengers movie.

As previously reported, a UEA spokesman confirmed the Sainsbury Centre had been booked out until the end of the day but said they were unable to comment further.