Erin Dietrich/Jenelle Evans' Facebook

Nathan Griffith Goes Shirtless For Son Kaiser's Birth Announcement Pics

The 'Teen Mom 2' cast member shows off his new baby -- plus a little skin.

Nathan Griffith is bonding with his bouncing baby boy Kaiser -- and showing off his buff body in the process.

Jenelle Evans, who welcomed her second son on last week's heartwarming episode of "Teen Mom 2," shared some professional photographs of her new offspring on her Facebook page, and her beau's pecs are almost just as eye-catching as the little guy.

Erin Dietrich/Jenelle Evans' Facebook

The young dad, clad in only jeans, looks rock-solid as he cradles his mini-me -- but we're not surprised considering his dedication to fitness. Meanwhile, Jenelle also enjoyed some quality cuddle time with her munchkin, who's comfortably wrapped in a blue blanket for his closeup with mom.

Erin Dietrich/Jenelle Evans' Facebook

"I am so proud of this!" she captioned the lovely family album.

+ What do you think of the photos? Sound off in the comments, then relive Kaiser's debut below. And be sure to catch a new episode of "Teen Mom 2" tonight at 10/9c!