The 26-year-old, who finished 7th in the U23 road race at the 2014 World Championships, has spent the last three years at Manzana Postobon, the Pro Continental team that is a renowned developer of Colombian talent.
He rode and finished the Vuelta a España as the team made their Grand Tour debut, while this year he rode a string of races in Spain and France before finishing runner-up at the Tour of Quinghai Lake.
He has effectively been brought to the team by López, with whom he is good friends and trains on a regular basis.
"I am grateful to Astana Pro Team for this huge opportunity," said Bohórquez in a statement from the team.
"I am very happy and super motivated coming to this fantastic project. I am ready to give my all to help the team in reaching the biggest goals. I hope the new 2019 season will be a very exciting and successful for the whole Astana Team."
Bohórquez joins the team on a one-year deal and will line up alongside López in his chosen Grand Tours. Astana have yet to draw up their Grand Tour plans for 2019, with López set to share the calendar with Jakub Fuglsang. This year López rode the Giro d'Italia and Vuelta a España and finished third overall at both.
"We are curious about the WorldTour start of Hernando Bohórquez, but he already showed some strong performances in Europe, especially at the World Championships," said Astana manager Alexandre Vinokourov.
"We bring Hernando as a rider, who can provide a good help in the high mountains to our leader Miguel Angel Lopez. They know each other very well, they train together and I think, this could help the team at the Grand tours. Let's see how it will work in 2019."