"He's definitely in love with Amal, and isn't having second thoughts about marrying her. However, he's definitely having serious wedding jitters," showbizspy quoted a source as saying.
The 53-year-old actor is scared of having a failed marriage again.
"He's so afraid he's going to fail at marriage again, and the thought of going through another divorce scares him to death. Just talking about the wedding plans makes him break out in a sweat," added the source.
The actor's friends have told him to calm down and embrace the fact that he's met the woman he wants to spend the rest of his life with and that he should just go with it.