Mimi O'Donnell, Philip's partner of 14 years, was visibly distraught as she left her New York apartment for the ceremony with the couple's three children, Cooper, 10, Tallulah, seven, and five-year-old Willa.
She entered the Frank E. Campbell funeral home shortly before 5pm, followed moments later by the actor's mother Marilyn O'Connor.
Philip's co-stars then began to solemnly process inside to pay their respects to the Capote star, and his loved ones.
Doubt co-star Meryl arrived with her husband Dom Gummer, while Cate, who was among those to visit Mimi at her home, was supported by her spouse, director Andrew Upton.
Ben Stiller, close family friend Justin Theroux, director Mike Nicholls and his wife Diane Sawyer also attended the sombre event, alongside Amy Adams and Joaquin Phoenix. Michelle Williams was crying as she was driven away after the wake.
Amy also broke down in tears this week during an appearance on Inside the Actors Studio.
"(Host) James Lipton asked her about working with Philip on Doubt and The Master. It hit a nerve with her," an insider told US Magazine. "(Amy) was sobbing and couldn't finish most of her sentences.
"Amy walked about how he was one of the greatest actors she had worked with, and couldn't even tell stories about him without crying. She said to the audience of acting students, 'I wish you all could have had the chance to work with him.'"
Philip, regarded as one of the best actors of his generation, was found dead in his West Village apartment on Sunday morning after a suspected heroin overdose. He was 46.
Since then, police have arrested four people in connection with the drugs found in his home.
A private funeral service for relatives and close friends will be held at St Ignatius of Loyola on Friday, and a larger memorial service will be held later this month.