US comedian Bob Newhart has been warned by gay activist groups against his scheduled appearance at the summit of a Catholic magazine which calls homosexuality a “disorder” that must be “cured.”

GLAAD has asked the 84-year-old comedian not to attend the summit for Legatus scheduled for next year, which would include anti-gay figures such as Rick Santorum and Bill Donahue.

In a blog post, GLAAD Special Projects Consultant Jeremy Hooper warned Newhart against becoming “the next Kirk Cameron.”

He wrote: “Personally, I’m choosing to believe that he just doesn’t know and that this booking is the result of bad advice.”

Former child star Kirk Cameron has been lambasted in the past for his comments labelling homosexuality and gay marriage ‘destructive’, ‘unnatural’ and ‘detrimental’.

Mr Hooper reported the magazine instructed readers to vote against political candidates in support of equal marriage, and also called the idea of homosexuality a “disorder” which must be “cured.”

He added: “GLAAD is reaching out to Mr Newhart’s representatives to let them know how, exactly, an appearance at this event will come across to LGBT people and allied voices.

“I am hoping that I am right, and Mr. Newhart doesn’t want to go down that path.”

Mr Newhart recently won his first Emmy after appearing in a guest role alongside gay actor Jim Parsons in The Big Bang Theory.

The magazine Legatus, which promotes itself as “a membership organisation for top-ranking Catholic business leaders,” was launched in 1987 by Domino’s pizza founder Tom Monaghan.