Ryan Reynolds thumb-wrestles with daughter James, teases ‘Deadpool’

Blake Lively's proclivity to Instagram has swept up Ryan Reynolds: The first-time mom heralded her husband's arrival to the photo-sharing app by showcasing his picture of their newborn daughter, James.

Well, part of James. And by part we mean hand, because that's all you can see of her in Reynolds' post.

"Thumb wrestling isn't always fair. Curiously, my hand is the small one," the actor joked, sharing a snapshot of his digits coming together with his daughter's.

Lively regrammed the photo, adding the caption, "...and with that, my husband @vancityreynolds joins Insta."

Thumb wrestling isn't always fair. Curiously, my hand is the small one.

A photo posted by Ryan Reynolds (@vancityreynolds) on May 14, 2015 at 9:47am PDT

It's the first pic the goofy pair has shared of their baby girl, and hopefully not the last.

The "Gossip Girl" alum has given multiple shout-outs to her husband of nearly three years on the site, gibing at his gushy gaze, his "Woman in Gold" costar Helen Mirren, admiring his beefed-up physique and highlighting a memorable "Reynolds vs. Reynolds" pose-off. (We're going to let that last one speak for itself.)

Should I be concerned that my husband's never looked at me this way?... #WhereAreThoseEyesWanderingReynolds #HelenMirrenIStheSexiestWomanAlive #WomanInGold

A photo posted by Blake Lively (@blakelively) on Apr 3, 2015 at 9:27pm PDT

"...it all started with a spider" -Walt Disney

A photo posted by Blake Lively (@blakelively) on Apr 27, 2015 at 1:24pm PDT

Now for this week's WHO WORE IT BETTER... Reynolds vs Reynolds I vote for a reshoot:wearing only the mask. #Deadpool #RyanReynoldsRocksMySocks #CanSomeonePleaseGiveThatBearABreak

A photo posted by Blake Lively (@blakelively) on Mar 27, 2015 at 6:44pm PDT

Likewise, the Canadian actor already has a knack for the app, sharing two buzz-worthy pics on the site in his first week of engagement.

PHOTOS: Blake Lively and Ryan Reynolds through the years

His public use of the app actually kicked off on Monday when he posted a snapshot of himself in character as the titular star of 2016's "X-Men" spinoff "Deadpool."

Toting two guns, the assassin is showcased in a gritty snap leaping head-first over a car, which the actor summed up this way: "Stuck the landing. With my mouth."

Stuck the landing. With my mouth.

A photo posted by Ryan Reynolds (@vancityreynolds) on May 11, 2015 at 11:13am PDT

Reynolds is no stranger to the world of superheroes: Back in 2011, when he was still married to "Avengers" actress Scarlett Johansson, he played DC Comics' Green Lantern in the action flick of the same name. Lively was his costar.

Here's to more set photos and a bit more behind-the-scenes action.

Follow me on Twitter @NardineSaad.