Cher [ tickets ], currently in the midst of a lengthy farewell tour, has postponed several shows while she battles throat problems.

The singer, who recently added a string of dates that extends her U.S. run into August, postponed her Tuesday (5/20) show in Rockford, Ill.; her Thursday (5/22) show in Milwaukee; and her Friday (5/23) show in Ft. Wayne, Ind.; in order to recover from a "severe throat infection," according to her official website. Those shows are now scheduled to take place on July 28, Aug. 6 and Aug. 16, respectively.

She has also bumped her June 8 concert at the Bryce Jordan Center in University Park, Pa., back to July 8.

Cher, who turned 57 on Tuesday (5/20), last June launched what she said will be her final tour, and has been on the road almost non-stop ever since. Her set list encompasses material from throughout her nearly 40-year career.

In March, Warner Bros. issued "The Very Best of Cher," a career-spanning set that includes the tracks "I Got You Babe," "The Beat Goes On," "Gypsies, Tramps & Thieves," "Half-Breed," "Song for the Lonely," "Believe," and many others.

Cher's recording career began in 1965, and she released her most recent studio album, "Living Proof," last February. It spawned the hit "Song for the Lonely."

Cher first rose to fame with partner and then-spouse Sonny Bono. During her subsequent solo career, she has enjoyed several cycles of prominent commercial success, the most recent of which occurred in 1998. It was during that year that her single "Believe," featured on the album of the same name, hit No. 1.

The song went on to garner Cher the 1999 GRAMMY^® award for Best Dance Recording.