The Spain international spent around seven years in the Barcelona academy before he completed a move to Dinamo Zagreb in 2014.
After spending six years with the Croatian outfit, the 26-year-old made the switch to German club Leipzig in January 2020.
Olmo has gone on to establish himself as a key player in the Leipzig side, scoring 29 goals and providing 34 assists in 148 appearances.
The Spaniard also played a starring role in Spain's Euro 2024 success, scoring three goals and providing two assists in six appearances.
Barcelona agree Olmo deal
Having impressed for club and country, Olmo has emerged as one of Barcelona's main transfer targets for the summer transfer window.
Leipzig boss Marco Rose recently insisted that Barcelona must meet Olmo's "value" after failing with their first two bids.
However, according to journalist Fabrizio Romano, Barcelona have now reached a verbal agreement with Leipzig over a deal for Olmo.
Barcelona sporting director Deco travelled to Leipzig to agree a €55m (£47.4m) deal which contains a further €7m (£6m) in add-ons.
Olmo had given his approval prior to the agreement between the two clubs and is set to sign a six-year contract once negotiations are finalised.
Where will Olmo play at Barcelona?
Olmo has travelled to Barcelona with his father Miquel Olmo and his agent Andy Bara as he closes in on a return to the Catalan giants.
The Barcelona academy product will likely compete with Pedri and Fermin Lopez for the attacking midfield spot in Hansi Flick's side.
Olmo can also operate on the flanks and will add to Barcelona's current wide options of Lamine Yamal, Raphinha and Ansu Fati.
The imminent arrival will not feature in Tuesday's friendly against AC Milan, but he could be signed in time to play in the Joan Gamper Trophy match against Monaco on Monday.
If everything goes according to plan, Olmo could make his competitive debut in Barcelona's La Liga opener against Valencia on August 17.