Pop superstar Cher has been left heartbroken after learning her longtime costume designer, Bob Mackie, will no longer be able to dress her for her upcoming farewell tour.

The Believe hitmaker announced plans last year (13) to hit the road for one final tour in 2014, and in August (13), she expressed her delight after discovering MACkie would be responsible for creating her onstage wardrobe once again.

Taking to Twitter.com, she wrote, "Just heard that Bob will make costumes for the tour. It makes me so unbelievably happy! Last time around, wouldn't be me without him."

However, other commitments have since prompted 73-year-old MACkie to withdraw, leaving Cher to put her faith in Hugh Durant, a British designer she previously worked with in 2003.

Breaking the news to fans on Thursday (13Mar14), she tweets, "The Show Looks Insane... Dancers Costumes R (sic) Gorgeous .... I On The Other Hand Have A Problem... WAS PUTTING OFF Telling you Something That Has Broken My Heart... The Man Who Made All My Costumes Since 1972 Decided He Couldnt (sic) Do My Last Tour...

"No Matter How Disappointed Any Of U Are, You Dont (sic) Know My Grief. Im Sure Bob Cant (sic) Know How Much I Miss Him.Felt I Had To Tell U Im (sic) Crying...

"I Tried To Convince Him... But He Had Many Reasons As 2 (sic) Why He couldn't do it. 2 many obligations Not Enough Time Even 2 Do 1 (sic)...

"Thank God I Have A Lovely Man & Wonderful Designer !! Hugh Durant. He Is Talented & Brave... We Will Persevere".

The 67 year old will kick off her Dressed To Kill Tour in Phoenix, Arizona next week (22Mar14).

MACkie, who has dressed the likes of Tina Turner, Liza Minnelli, Carol Burnett, Diana Ross and Whitney Houston, was famous for creating revealing sequinned and feathered outfits for Cher, including the barely-there black ensemble she wore to the Academy Awards in 1988, when she won the Best Actress honour for Moonstruck.