Ryan Reynolds shares first photo of daughter James

Ryan Reynolds isn't wasting any time now that he's on Instagram -- after joining the platform earlier this week, he's already posted a "Deadpool" sneak peek and now the first photo of daughter James.

Well, her little hand, at least.

"Thumb wrestling isn't always fair. Curiously, my hand is the small one," he captioned the snapshot, showing her gripping his thumb.

Reynolds and wife Blake Lively welcomed baby James in December. Since then, they've kept the details on their little one very quiet -- not even officially confirming her name until a month ago.