South Korea's top court Thursday upheld a lower court decision that sentenced a longtime confidante of former President Park Geun-hye to 18 years in prison over a corruption scandal that led to her 2017 ouster.

Choi Soon-sil also faces a fine of 20 billion won (about $16.8 million) and a 6.3 billion won forfeiture for conspiring with the then president to pressure conglomerates including Samsung Group to donate large sums, among other crimes.

Both Choi and prosecutors had appealed to the Supreme Court the Seoul High Court ruling that came out in February. The 63-year-old had pleaded not guilty.

Park, 68, is being tried separately. With Choi's guilty verdict finalized, the top court is very likely to find Park guilty as well in connection with the case.

Choi was arrested in November 2016 over an abuse-of-power case involving former aides to Park. She was initially sentenced to 20 years in prison. But the Supreme Court last August ordered a retrial and sent her case back to the Seoul High Court.

Similarly, Park was previously found guilty and given a decades-long prison term, but the Supreme Court later sent her case back to a lower court, citing a violation of rules for trying crimes.

In the latest trial, prosecutors have demanded that Park be sentenced to a total of 35 years in prison over bribery, abuse of power and embezzlement charges in connection with this and another case.

The Seoul High Court is set to issue a ruling on July 10.