Rev Donald Hegan said he could understand why someone stole Grylls - it's the same reason Alfa uses him as a poster boy.
''He's out there, he's a survivalist, he's a guy who can make it in the wild and I think young people respect him.''
The church has put up a new sign, with another face of Grylls.
''I think he's safely ensconced in someone's flat but I'm hoping they leave this one alone. I haven't got any more reserves.''
Rev Hegan said the church had decided to make the best out of the situation rather than getting bitter about the theft.
The Alpha course has been attended by more than 16 million people in 164 countries, Bear Grylls being one of them.
The Alpha course begins next Thursday night at St Columba church with a gold coin koha introductory meal. The course runs for seven Thursday nights.
Having Bear Grylls promoting a Christian course challenges stereotypes about what Christians are like, he said.
''It breaks the stereotype of wimpish people who can't enjoy life.''