Katherine Heigl brought 8 week old baby Josh Jr. with her when she visited the Late Late Show With James Corden last night (February 14th). As the host announced his celebrity guests which included Lars Ulrich and Andrew Rannells, he paused after introducing Katherine and the camera cut to her dressing room backstage.

Katherine Heigl, Josh Kelley & Baby Josh Jr. Backstage At The Late Late Show

"Shh, look it’s a little baby in there!" Corden said, hushing the cheering studio audience. "Who’s this Katherine?" James whispered. " This is Josh Jr.," Katherine replied.

Katherine Heigl, Josh Kelley & Baby Josh Jr. Backstage At The Late Late Show

Josh Jr., dressed for the occasion in a very dapper bow tie, was oblivious to all the fuss as he rested peacefully, cuddled in his mom’s arm.

Katherine Heigl, Josh Kelley & Baby Josh Jr. Backstage At The Late Late Show

"So beautiful. Katherine, and Josh Jr. making his television debut tonight!" Corden announced. "How old is Josh " he quizzed. "Eight weeks today," Katherine said, adding "He’s serious," with a laugh, as the little guy held a stoic expression for the camera.

Katherine Heigl, Lars Ulrich & Andrew Rannells With James Corden On The Late Late Show

In Los Angeles on Valentine’s Day to promote the February 15 premiere of her new CBS legal drama Doubt, Katherine recalled how she used singer John Mayer as leverage in her own love life to gauge how her then-boyfriend, Josh Kelley, was feeling about their new relationship.

Katherine was reduced to tears of laugher when guest Andrew Rannells, educated everyone about the process of stuffing a male’s private parts into a special sock for nude scenes.

The Doubt star also got to tell Metallica drummer Lars Ulrich about how her former Roswell co-star Brendan Fehr used to play the bands music continuously when they shared a trailer on set.

The host and his celebrity guests also found time to ham it up for the camera, sharing a selfie on social media.

Katherine Heigl, Lars Ulrich & Andrew Rannells With James Corden On The Late Late Show

To watch the episode in full, visit the CBS Late Late Show website.