Minnelli performed at Michael Jackson's concert
The star has recently undergone back surgery and hip replacements which caused her weight to balloon.
But now the Oscar-winning actress is fighting back by appearing in a new touring show produced by her fiance David Gest.
Minnelli recently announced her engagement, setting a date in March for a lavish wedding.
Her first UK show in more than five years will feature a mix of new material and classic showstoppers.
Best man
Minnelli's spokesman said she was back to full health and added: "I think people will be really surprised when they see her again."
The 55-year-old will visit the UK later in January to unveil details of the show.
It will debut in London on 2 April before travelling to venues in Europe.
Liza Minnelli's wedding will feature an all-star cast of celebrities as she ties the knot for a fourth time.
Dame Elizabeth Taylor is maid of honour and Michael Jackson and his brother Tito are acting as best men.
Convert
Whitney Houston will also be singing Here Comes the Bride during the ceremony.
The Academy Award-winning actress is currently converting to Catholicism so that she can marry in America's top cathedral.
Minnelli has battled against health problems over the last few years.
After undergoing back surgery and two hip replacements she was forced to cancel 14 concerts in 2000.
Minnelli made her first public appearance after the treatment in New York on 7 September 2001, at Jackson's comeback concert.
In what was seen as her return from illness she sang You Are Not Alone at the Madison Square Gardens venue.
Minnelli was born in March 1946 to screen legend Judy Garland.
It was in 1972 that she emerged from the shadow of her mother with a show-stopping performance in the hit musical Cabaret, a role which earned her an Academy Award.