The two budding young actors were taken to the auditions by their drama tutor, Lesley McDonough, of Activate drama school in Sunderland.
But little did the youngsters realise they were about to land main roles in a show that has the country's youngsters enthralled.
Proud parent Andrea Anderson said: "Neither of the girls has ever done anything like this before, but they both got parts and they absolutely loved it.
"We're all over the moon with them both and so proud. We can't wait to watch it on TV."
For the filming of the new series, Tracy Beaker Returns, Tracy is all grown up and, at the age of 20, returns to the home, but this time as a carer.
Katie, who plays Poppy, and Claudia, who plays Rosie, will both be living their acting dreams when they step into the shoes of kids living in the care home.
In July, Katie and Claudia started their adventure when filming began in Newcastle when the former La Sagesse School in Jesmond was transformed into the set for the school.
Andrea said: "They absolutely loved it. In fact, Katie's turned into a right little diva now and, apparently, I'm her servant.
"This is something she would love to do again."
Tracy Beaker Returns is now showing every Friday at 17:15 pm on the CBBC channel.