Robert Pattinson on a guy's night out in Hollywood going to Larchmont restaurant until 1 am with friends Vince Vaughn and Joaquin Phoenix. Credit: X17online

Three guys walk into a restaurant. That may sound like the beginning of a joke, but it's actually the beginning of something else: Robert Pattinson's boys' night out with Vince Vaughn and Joaquin Phoenix. On Friday, April 5, the unlikely trio were spotted hitting the town together in L.A.

Pattinson, 26, joined Vaughn, 43, and Phoenix, 38, at the Larchmont Restaurant in Larchmont Village, where they grabbed dinner with a few other friends. It's unclear what else they did -- or how they all know one another.

One thing they have in common? Reese Witherspoon. All three have appeared opposite the Oscar-winning star in various films over the last decade. Phoenix was Johnny Cash to her June Carter in 2005's Walk the Line, for which she won the Academy Award; Vaughn played her leading man in the 2008 rom-com Four Christmases; and Pattinson rescued her from an abusive circus trainer in the 2011 movie adaptation of Water for Elephants.

Pattinson -- whom his former costar has called a "very sensitive soul" -- also famously hid out at the actress' Ojai, Calif., ranch last July, after Kristen Stewart was caught cheating on him with her Snow White and the Huntsman director, Rupert Sanders. (A source told Us Weekly at the time that Witherspoon hoped the rustic retreat would have a "calming effect" on the Twilight actor as he dealt with his heartache.)

Since then, of course, Pattinson and Stewart have reconciled. Earlier this week, before the actor's boys' night out, the two were spotted holding hands and grabbing sushi together in L.A.'s Los Feliz neighborhood. They looked "really happy and lovey-dovey," an eyewitness told PopSugar. "Kristen grabbed his arm, and they were walking and joking."