It looks like Sienna Miller wasn't the only female G.I. Joe cast member that was smitten with veteran Korean actor Lee Byung Hun. According to Channel News Asia, it seems that fellow cast member Rachel Nichols was smitten with Lee Byung Hun's abs, not to mention she thinks he's hot, an excerpt from the article:

Whose idea was it to get Lee to take his shirt off? Rachel Nichols (RN): Mine! I didn't even need to work that day; I just turned up on set anyway. Marlon Wayans (MW): She was like: "Get his shirt off, get his shirt off!" Lee Byung Hun (LBH): I had to work out so hard. I never drank - not even one bottle of beer. I had to be on a diet. I thought: "I'm not an actor; I'm a body builder." I was a little disappointed, though, because Stephen deleted a lot of those scenes. Stephen Sommers (SS): He wanted slow motion shots! We'll probably put those in the DVD. Rachel Nichols (RN): We'll make a whole movie out of those shots! ... Stephen, what made you pick Lee for the role? Stephen Sommers (SS): Someone showed me a movie of his - I can't remember which one now - and I thought: "He's a movie star." He projects so much with his eyes. There's something about this guy ... I don't know. I love him! Rachel Nichols (RN) (To Stephen) I think all of your answers should be: "Because he's hot!" Stephen Sommers (SS): Because he's hot! And I'm not gay!

The article also mentions that Marlon Wayans and Lee Byung Hun became best friends, which is pretty cool! Good to hear positive news for Lee Byung Hun in Hollywood!