The original deal had the 59-year-old entertainer performing “Manilow: Music and Passion” for 24 weeks through 2005 and into 2006.

“In his first ten weeks of performing at the Las Vegas Hilton, Barry has been a top Las Vegas draw, along with Celine and Elton (John), and he leads the Hilton’s exciting new entertainment roster,” said Ken Ciancimino, Hilton executive vice president.

The show opened Feb. 23 in a 1,700-seat theater. Manilow promised the next 150 shows will be filled with surprises.

“I’ve always avoided a fixed show that repeated the same thing every night,” Manilow said in a statement. “I’m glad that the Las Vegas Hilton and `Music and Passion’ have given us all the chance to surprise the audience every night.”

Tickets for the newly added shows will be on sale August 13. Prices range from $85 to $225.