Little Toby Papworth appears on camera FOUR times and his name is in the credits for the movie that has already made £750million at the box office.
He even features in trailers shown worldwide for Harry Potter and the Deathly Hallows - Part 2. Toby's fee would not cover two tickets to see it in IMAX 3D cinemas.
Mum Ashley, 26, who had to PAY to see the movie, said yesterday: "I couldn't believe my eyes when I got the cheque.
"I was told he would get a standard extra's fee for the day, but they promised to try to get more if he appeared in the film."
Ashley had taken 20-month-old Toby for a day's filming at Leavesden Studios, Herts, after an agency found him the part.
He was given his own dressing room and his mum got a £90 chaperone fee. Toby was on set twice in the morning and twice in the afternoon.
In a flashback in the film he is seen clutching the wooden bars of a cot as Harry's parents try to protect him from Lord Voldemort. The evil mastermind murders his parents and fires a killer curse at Harry, played in the films by Daniel Radcliffe.
Ashley said: "I had to get Toby to look in certain directions by teasing him with his favourite toys.
"He was one of two babies filmed for the part, but I didn't know his scenes had been chosen until June.
"Then I started seeing the trailers on TV and I realised his little face was being seen all over the world.
"On one hand I was over the moon because his scene is quite a major one. But on the other, the filmmakers didn't so much as send me a ticket.
"I phoned Toby's agency when the cheque came and they told me that was all he was getting - just £40."
Police worker Ashley, of Ilford, Essex, said: "Considering he was a named part, it seems a bit mean. That said, we had a great day."
Warner Bros said fees were set by an external company.