Andrew Lloyd Webber's son 'critically ill' with cancer as he's hospitalised

Devastated Andrew Lloyd Webber has revealed his eldest son Nick is 'critically ill' with cancer.

Nicholas Lloyd Webber, 43, has been hospitalised 18 months after he was diagnosed with gastric cancer.

"I am absolutely devastated to say that my eldest son Nick is critically ill," Andrew said in a statement.

“As my friends and family know, he has been fighting gastric cancer for the last 18 months and Nick is now hospitalised."

He added: "We are all praying that Nick will turn the corner. He is bravely fighting with his indomitable humour, but at the moment my place is with him and the family.”

Andrew Lloyd Webber has revealed his son has gastric cancer (AP)

Andrew explained his son's illness was the reason he wasn't able to attend the Broadway launch of his latest musical, Bad Cinderella.

The 74-year-old composer said: "I will not be able to cheer on its wonderful cast, crew and orchestra on Opening night."

The musical earned a recent Grammy nomination for best musical theatre album.

Nicholas is the eldest of Andrew's five children, from his first marriage to composer Sarah Hugill.

Andrew with his oldest children Nicholas and Imogen when they were little (RICHARD YOUNG / Rex Features)

The composer is known for his work scoring the BBC One series Love, Lies and Records, and the film The Last Bus.

Andrew shares Nicholas, 43, and Imogen, 44, with ex-wife Sarah. Andrew went on to have three more children with second wife Madeline Gurdon.

The couple share sons Alasdair, 30, and William, 29, as well as 26-year-old daughter Isabella.

Prior to that Andrew was also married to West End star Sarah Brightman for seven years until they divorced in 1990.

Andrew with son Nick (left), who he revealed is now critically ill (Facebook)

Andrew had been scheduled to attend a press event for Bad Cinderella in New York press event on Wednesday - the same date as his 75th birthday.

The musical is adapted from the well-known fairytale, and features original songs from Lloyd Webber, who wrote additional new material for the Broadway run.

The production stars Linedy Genao in the title role, with a supporting cast, including Jordan Dobson, Grace McLean, Carolee Carmello, Sami Gayle, Morgan Higgins and Christina Acosta Robinson.

Bad Cinderella opens Thursday, March 23, at the Imperial Theatre.