He has been chosen above his former partner Elizabeth Hurley, who is not listed, and his entry reveals that his middle names are John and Mungo.
NEW IN WHO'S WHO
Also among the new entries are comic and writer Meera Syal, Gosford Park stars Emily Watson and Jeremy Northam.
Gosford Park is represented in another new inclusion, with its Oscar-winning screenwriter Julian Fellowes' entry saying he does "too little sport and too much eating".
They are among 1,000 new entries, also including sports stars Ellen MacArthur, Steve Cram and Jonathan Edwards.
Hugh Grant's mini-biography lists his hobbies as football and singing, although he recently said that he sings "like a hyena".
The actor has enjoyed a successful year, with his comedy About A Boy earning a Golden Globe nomination, becoming an outside bet for Oscars success.
Meera Syal stars in The Kumars at No 42 and Goodness Gracious Me, and wrote both the novel and screenplay for Anita and Me.
She lists her hobbies as netball and jazz singing.
'Next James Bond'
Emily Watson is listed after becoming one of the UK's most respected young actresses, with parts in Gosford Park, Punch-Drunk Love and Hannibal Lecter prequel Red Dragon.
Northam, tipped by some as the next James Bond, played composer Ivor Novello in Gosford Park, and has also recently been seen in Enigma, Possession and as Dean Martin in TV biopic Martin and Lewis.
Another new entry is children's author Melvin Burgess, whose books dealing with teen drug addiction and sex have caused controversy.
The 155th edition of the directory, which includes more than 32,000 profiles, will go on sale on Friday for £130.