The official, who was not authorized to discuss the case publicly and spoke on condition of anonymity, confirmed that investigators have formally asked del Castillo to meet with them about the encounter she and Penn had with Guzman.
The official said Monday that it is unclear when that will happen and added that del Castillo is considered a witness and is not accused of any crime.
Guzman is the Sinaloa drug cartel capo who was captured earlier this month in Los Mochis, Sinaloa state, six months after escaping from a maximum-security prison.
Del Castillo is perhaps best known to American audiences as crime boss Pilar Zuazo on the Showtime show "Weeds," as well as her starring role in the 2007 hit movie "Under the Same Moon." The 43-year-old Del Castillo had her most memorable role in 2011 playing a drug kingpin in "The Queen of the South," a very popular TV series based on a book written by Spanish writer Arturo Pérez-Reverte.
Penn's article about Guzman was published by Rolling Stone the day after his capture. Mexican officials have said the meeting between Penn, del Castillo and El Chapo helped lead to the drug lord's capture.
Eduardo Sanchez, spokesman for Mexico's presidency, said last week that the government would investigate whether a crime was committed during the meeting between the drug lord and the actors, but that there was no criminal probe of Penn or del Castillo.
However he criticized the idea that someone with information about a wanted fugitive would not share it with authorities.
Officials have said Guzman appears to have been infatuated with del Castillo, apparently referring to her by the code name "Hermosa," or "Beautiful." The drug lord also wanted a second meeting with her according to the official, who was not authorized to be quoted by name.
Penn said after his meeting with Guzman that the drug lord "was interested in seeing the story of his life told on film, but would entrust its telling only to Kate."
Del Castillo responded to criticism about her meeting last week via Twitter.