'This Is Us' actor Chris Sullivan, wife Rachel expecting first child together

"

This is Us

" star Chris Sullivan and his wife

Rachel Reichard

are set to welcome their first child together.

Sullivan shared the news on Instagram.

"We're having our first baby! And we just found out the sex. Swipe through for the gender reveal," he captioned the sonogram.

"It's true! You heard it from @sullivangrams we are having a BOY!! So excited!!" Rachel wrote on her Instagram account.

Sullivan's "This Is Us" co-stars congratulated the couple.