The 24-year-old actor was thrilled to find out that he had been offered the part of Credence in the fantasy film and Watson told him to "buckle his seatbelt," reported Female First.
"Emma was delighted; she knew what the books had meant to me as a young person so she could imagine how much joy I was feeling. She said wonderful things about Jo, about David (Yates) and about Eddie. She worked with Eddie on 'My Week With Marilyn'.
"She just told me to buckle my seatbelts on all of my limbs and digits and prepare for a fun ride. Keep my hands and feet inside the vehicle at all times," Miller said.