Aretha Franklin smiles after the Detroit Pistons-Miami Heat NBA basketball game in Auburn Hills, Mich., Friday, Feb. 11, 2011.

*Aretha Franklin says she’s back at “150 percent” and has announced the date of her first scheduled concert to take place since undergoing surgery.

Franklin said in an interview Wednesday with The Associated Press that she’s set to perform at the Seneca Niagara Casino in Buffalo, N.Y., on May 28. It’s the same month that she said her new album “Aretha: A Woman Falling Out of Love” becomes available in Wal-Mart Stores.

The Queen of Soul had surgery in December for an undisclosed ailment.  Some reports claimed it was a procedure to treat pancreatic cancer (reports she has outright denied) while other talk has suggested she suffered severe complications from gastric bypass surgery.  Franklin has opted not to disclose the exact nature of her operation.

The 68-year-old has since revamped her diet, giving up her beloved chitterlings, pigs’ feet and ham hocks in favor of a Whole Foods-type diet, reports the AP.

As seen in her videotaped Grammy appearance, she’s lost weight and hopes to get down to a size 16.