Chelsea Conor Gallagher will travel to Madrid on Monday with the intention of signing a five year contract for Atletico following a breakthrough in talks.
Atletico had agreed a £33.7million deal with Chelsea last week and were pressing for an answer by today.
Chelsea had made it clear to Gallagher that it was best for him to move on after 16 years at Stamford Bridge and talks accelerated with the club on Sunday with a resolution met in the early hours.
Gallagher will fly with his representative Paul Nicholls to Madrid to finalise terms and all is expected to be signed off for the England international later today.