Park, 69, underwent shoulder surgery in 2019 while serving her prison term, according to the Justice Ministry. She had been spotted by local media multiple times going to hospital in a wheelchair.

Speaking through her lawyer following the pardon Friday, Park apologized "to the people for causing so much concern."

"I will concentrate on getting treated and try to thank the people myself in the earliest time possible," Park said, as relayed by her lawyer Yoo Yeong-ha, who did not give details of her health condition.

Park has been hospitalized at the Samsung Medical Center in Seoul since November 22, the hospital's communication team confirmed to CNN, but the cause of her stay was not shared due to confidentiality.

Park also thanked President Moon and the government for granting her pardon.

The Blue House spokesperson added Moon hopes Park's pardon would be an opportunity to start a new era of unity and harmony and asked for understanding from those opposed to the decision.

Park, who has served about four years and eight months in prison, will be freed on December 31.

South Korea corruption scandal

The daughter of former dictator Park Chung-hee, Park Geun-hye became South Korea's first female President when she came to power in 2013 -- but her term was marred by controversy.

The 2017 vote to impeach Park came after millions of South Koreans took to the streets over a period of several months to demand her ouster, following revelations about the undue influence wielded by her adviser and confidant, Choi Soon-sil, the daughter of a cult leader.

Several others were also implicated in the scandal. In 2018, Park's confidant Choi was sentenced to 20 years in jail on 18 charges including abuse of power, coercion, fraud and bribe, and was fined $16.6 million.