Why Bogart was cast . . .
Just watched "Sabrina" for the 10th time in my life and finally found out why Bogart plays Linus. According to TCM's host (Ben M), the role of Linus was originally intended for Cary Grant, but eventually went to Bogart. He took the part with the
intention of having his wife, Lauren Bacall, play Sabrina. When that didn't work out, he was quite displeased but already locked in for the part. He didn't get along with Holden at all and wasn't happy about working with Audrey. When later asked how he liked working with Hepburn, he 'famously' said, "It's okay, if you don't mind doing 20 takes", putting him in the short list of actors who disliked working with her. (This is pretty much verbatim from Ben's commentary.) As it turned out, Hepburn wound up being nominated for an Oscar for Best Actress for her performance.
I like Bogart a lot but casting him in this part, given the fact that Hepburn played Sabrina, makes him look miscast in the film. IMHO, she's too young and 'delicate' to be paired with a love interest so 'worn out' looking as Bogart. It's one thing to 'play against type' but I feel he seems far too old for her character to fall in love with here and there's just no chemistry between them. C'est la vie en l'industrie du film!