OKLAHOMA CITY — Oklahoma Supreme Court Justice Joseph Watt plans to retire at the end of the year after 25 years on the state’s highest court.

The 70-year-old Watt announced his retirement, effective on Dec. 31, in a letter to Gov. Mary Fallin on Monday.

Former Gov. David Walters appointed Watt to the Supreme Court on May 17, 1992, and he has served two terms as chief justice, from 2003 until 2007.

A native of Altus, Watt was appointed to a special district judge’s seat in Jackson County in 1985 and was elected associate district judge in 1986.

Fallin will appoint a new justice to the nine-member court from among three nominees chosen by the Judicial Nominating Commission. The appointment will be Fallins’ second to the court following Justice Patrick Wyrick in February.