TOM CRUISE may not have a new woman in his life, but it seems he has a new BFF!

The recently divorced actor’s constant companion of late has been nerdy Hollywood screenwriter/ director Christopher McQuarrie, who co-wrote “All You Need Is Kill,” the film Tom has been working on in England.

The bespectacled Oscar winner, 44, has been at Tom’s side nearly nonstop in London – including outings to Annabel’s nightclub, the Old Globe Theatre and director Ridley Scott’s restaurant in Mayfair.

“Tom and Christopher have become virtually inseparable,” said a source close to McQuarrie. “Not only did he write Tom’s current flick, he’s also become Tom’s go-to guy for films, in general.”

McQuarrie penned Tom’s 2008 Hitler assassination movie, “Valkyrie,” polished some of last year’s smash “Mission: Impossible – Ghost Protocol,” and wrote the screenplay and directed the upcoming cop drama, “Jack Reacher.”

McQuarrie was even planning a  highly anticipated sequel to Tom’s first major hit, 1986’s “Top Gun,” but that’s on hold due to the recent suicide of director Tony Scott.

In many recent photographs, McQuarrie can be seen just a step or two behind Tom, wearing dark-rimmed glasses and looking like a young Stephen King.

He’s also become Tom’s sounding board. The 50-year-old actor has poured his heart out to McQuarrie as he deals with his separation from his beloved daughter, Suri, whom he sees less often since his summer divorce from Katie Holmes. Suri has just started school in New York City.

“I haven’t had a meeting with Tom that was not interrupted by a phone call with his daughter,” McQuarrie told a reporter. “His heart is broken. He misses his little girl and works very hard at parenting.”

Ironically, McQuarrie and his wife Heather were close friends with Tom and Katie before the onetime power couple’s shocking divorce.

AND Heather is Katie’s partner in her Holmes & Yang fashion line.

“Even though Heather continues to work with Katie,” said the source, “it hasn’t affected Tom’s relationship with his new wingman Christopher one bit.”