Carry On actor Barbara Windsor, who was one of the final people to see Victor before he passed, was also at the service on Tuesday afternoon.
Sir Paul and Barbara arrived separately at St Paul's Church, in Covent Garden, London, and both dressed formally in traditional black.
While the Beatles singer wore a smart black suit with an overcoat and sunglasses, Barbara opted for a black two piece with pink pinstripes and a matching blouse.
The ex EastEnders star was greeted warmly by fans as they surrounded her and asked for autographs.
Sir Paul was also received well and gave a wave to the waiting crowds as he got out of his car.
Other notable attendees included Neil and Christine Hamilton, and stage stars Michael Ball and Christopher Biggins.
Veteran actor Victor, who starred in all three Beatles films, died at the age of 82 after a prolonged battle with cancer.
The Welsh star, who also appeared in a string of acclaimed movies as well as taking roles in the West End and on Broadway, died after a fight with pancreatic cancer.
Close friend Barbara Windsor, on whose Radio 2 show he made a recent appearance, was one of his final visitors before his death at a hospice in Monmouth.
Spinetti’s agent, Barry Burnett, said: 'He had cancer for a year, but he was very cheerful to the end. I spoke to him on Friday and he was talking about his plans and everything.'
The versatile actor was able to easily turn his hand from serious classical roles to comedy performances and roles in sitcoms.
He was also known as successful stage director, poetry writer and randomly became known for his appearances in a Jaffa Cake ad campaign as the Mad Jaffa Cake Eater.
However, for many fans, Spinetti will always be known for his roles in The Beatles’ three live action films - A Hard Day’s Night, Help! and Magical Mystery Tour.
It was his close friendship with the Beatles at the height of their fame which put him on the map.
Spinetti was born in Cwm, Wales, on September 2, 1933, attended Monmouth School and the Cardiff College of Music and Drama of which in later life he became a fellow.
However, his working life began as a waiter and factory worker before he sprang to prominence in three Beatles films of the 1960s: Hard Day’s Night, Help! and Magical Mystery Tour.
The late George Harrison once said to him: 'You have got to be in all our films. If you are not in them, my mum won’t come and see them because she fancies you.”
During his versatile career, Spinetti appeared in more than 30 films, including Zeffirelli’s The Taming of the Shrew, Under Milk Wood, with Elizabeth Taylor and Richard Burton, Voyage of the Damned, The Return of the Pink Panther, and The Krays.
His work with Joan Littlewood’s Theatre Workshop produced many memorable performances including Fings Ain’t Wot They Used T’Be and Oh! What a Lovely War, which transferred to New York, and for which he won a Tony Award for his role as an obnoxious drill sergeant.
His West End appearances included Expresso Bongo, Candide, Cat Among the Pigeons and Chitty, Chitty, Bang Bang, He also played the principal male character in the feminist play, Vagina Rex.
He also appeared on Broadway in The Hostage and The Philanthropist. With the Royal Shakespeare Company he appeared as Lord Foppington in The Relapse and as the archbishop in Richard III.
Spinetti also co-authored John Lennon In His Own Write, which he directed at the National Theatre. He also directed productions of Jesus Christ Superstar and Hair.
His many TV appearances included Take My Wife, and the sitcom An Actor’s Life For Me.
Spinetti also wrote poetry, notably Watchers Along The Mall, and prose which have appeared in several publications.
His memoirs, Victor Spinetti Up Front, was filled with anecdotes, including the claim that Princess Margaret was instrumental in securing the necessary censor permission for the first run of Oh! What a Lovely War.