Scarlett Johansson didn't let her shocking split from Ryan Reynolds

-- or his growing closeness to pal Sandra Bullock -- get her down over the weekend.

About two weeks after Reynolds, 34, filed for divorce from the actress following two years of marriage, Johansson, 26, hit the Hollywood Hills home of Jeremy Renner.

In honor of his 40th birthday, the Hurt Locker hunk hosted a dizzying array of A-listers at his pad: Johansson plus Colin Farrell, Charlize Theron, Christina Aguilera, Blake Lively, Leonardo DiCaprio, Ben Affleck, Rebecca Hall and others.

Credit: Jon Kopaloff/FilmMagic, usmagazine.com