Larry Hagman's mother scored the Best Actress in a Musical Tony for her portrayal of lead character Maria von Trapp in 1959, and it was purchased by a mystery buyer at the RR Auction sale in Cambridge, Massachusetts on Thursday (19Mar15).

The prize was originally acquired from Dallas star Hagman's estate.

Martin died in 1990, while her actor son lost his battle with cancer in 2012.

The role of Maria von Trapp was made world-famous in 1965 when Julie Andrews starred in a film adaptation of the hit stage show. The classic movie musical celebrates its 50th anniversary this year (15).