The winger joins Hibs from English giants Manchester City, who similarly sent him out on loan to Dutch outfit NAC Breda for the last two seasons.
"Hibernian can confirm that Thomas Agyepong has completed his registration at the club," Hibs announced via their official website on Wednesday.
"The 21-year-old is now awaiting the completion of the necessary visa process before joining up with Neil Lennon’s squad.
"The winger signed for Manchester City in 2015 from the Right to Dream Academy, spending his time since then on loan at Twente and then two seasons at NAC Breda.
"Thomas made his international debut for Ghana in June 2017, appearing in a 5-0 win over Ethiopia.
"He will wear the number 17 jersey at Hibernian."
Owing to a long injury layoff, he made 12 league appearances involving four starts for NAC in the Eredivisie last term.