Comedian Denis Leary has upset Catholic groups after mocking Christmas during his TV special DENIS LEARY'S MERRY F#%$IN' CHRISTMAS.

The RESCUE ME star, 48, jokes about lesbian nuns, the origins of Christmas and sings a song by OUR LADY OF PERPETUAL SUFFERING CHURCH CHOIR about a prostitute.

In one segment, Leary says, "Tonight we celebrate the birth of the baby Jesus, whose mom, Mary, just happens to be a virgin - even after she apparently gave birth to Jesus. At least that is what the Catholic Church would have you believe.

"Tom Cruise is taking a lot of s**t for belonging to a religion, Scientology, that believes aliens came to this planet 75 million years ago. That is nothing. I was raised Catholic. We believe Mary was a virgin and Jesus ended up walking on water, creating a bottomless jug of wine and rising from the dead."

After hearing Leary's jokes, BILL DONOHUE, president of the Catholic League For Religious Ad Civil Rights, fumes, "Hate speech dressed in humorous garb is still hate speech. Leary is obviously bedeviled by some disorder but nothing excuses this crap."

Donohue's colleague and Catholic League spokeswoman KIERA McCAFFREY adds, "Going after the Blessed Mother is the kind of thing that really gets our backs up."

In defence, TONY FOX from the Comedy Central TV channel, says, "Comedy Central is an adult network and we think Denis Leary has the right to speak freely about what he thinks is funny. We don't cave to pressure and we're not pulling the show off the air."