X17 XCLUSIVE - Kristen Stewart And Sean Penn Share A Warm Embrace And A Kiss!

Someone's super stoked to meet up with Sean Penn!

Now I'm 99.999% sure Rob Pattinson doesn't have anything to worry about seeing as Sean is more than twice his age, but the 49-year-old stud does seem to have a thing for young ladies (remember those Lindsay and Natalie Portman rumors?), so we're sure Rob's keeping tabs on his lady love.

Today we caught Kristen Stewart arriving for a meeting at the Montage Beverly Hills, and she just happened to bump into Sean as she stepped out of her green Mini Cooper!

An X17 photographer on the scene tells X17online exclusively:

"Kristen arrived at the hotel and happened to see Sean and he called over to her - he clearly recognized her. He went right up to her and gave her a VERY friendly hug and a big smooch on the cheek, and Kristen's reaction was priceless - we've never seen her look so elated before!"

The two worked together on Into The Wild back in 2007 - Penn directed and Stewart played Tracy, the teenage singer who has a crush on Emile Hirsch's character Christopher McCandless. It was a small cameo, but apparently KStew made an impression!

courtesy Paramount Vantage

So then Kristen went inside the hotel and Sean disappeared, but that smile on her face certainly didn't! Obviously little Miss Twilight still gets starstruck every now and then, so we think this is pretty cute!