Credit: Jon Kopaloff/FilmMagic

Single and loving it!

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.

Johansson's pal for the night? Kevin Connolly, an insider tells"They were together all night and talked," the source says.

Was it romantic? "They weren't kissing, just drinking together."

According to the onlooker, Johansson chatted up Connolly, DiCaprio plus a "bunch of agents. They were standing there listening to her."

Adds the witness of the Iron Man 2 actress: "She was having a great time. There was no drama with her. She was running around the party and was a party girl, bouncing around from person to person."