Dick Van Dyke had a dialect coach "practically handcuffed" to him on the set of 'Mary Poppins Returns'.
The 91-year-old actor faced much mockery for his British accent in the original movie - in which he played both Jack-of-all-trades Bert, and bank director Mr. Dawes Sr - and so producers are taking no chances with his cameo in the sequel.
He said: "They had a dialectician practically handcuffed to me, to make sure this time the dialect was right. I wasn't a cockney this time, but they still wanted to make sure the accent was right."
This time around, Dick appears in a scene with the old banker and "thoroughly enjoyed" his short stint filming.
He said: "This time I play his son, who is not a nice guy. I got to jump up on a desk and do a song-and-dance number, and I thoroughly enjoyed it."
The new movie will see Emily Blunt take over from Dame Julie Andrews as the magical nanny, and the screen veteran thinks she was the perfect choice for the role.
He told the New York Post newspaper's Page Six column: I just got back from London, filming a cameo in the sequel for the new 'Mary Poppins.' People say sequels don't work, but the people behind it have their hearts in the right place. They insist it is not a sequel, it is an homage.
"Emily Blunt is a quite good Mary Poppins; she sings well. And they had re-created the original set of Cherry Tree Lane just perfectly that brought back a lot of memories.
"I was the only original member of the cast who is in it. It's like bookends for me. And Lin-Manuel [Miranda], who plays the lamplighter, dances very well, I was impressed."