Heidi Montag wants a baby, but according to a Marriage Boot Camp sneak peek, her husband isn't on board.

'The Hills' Star Holly Montag Is Pregnant, Sister Heidi Wants To Be Next

Years after they wrapped filming on MTV's The Hills, Montag and husband Spencer Pratt are returning to reality TV in Marriage Boot Camp, where they will be seen addressing a major issue in their marriage: children.

"We've been married for six years," Montag explained in her introduction to the series, according to a report by Us Weekly on Monday. "We are in boot camp to get over our regrets about the past and fear about the future. I'm ready to have children and Spencer's acting like a child and not ready for one."

Heidi Montag & Spencer Pratt Are Planning For Baby?

After becoming engaged during a trip to Santa Barbara, Calif. on an episode of The Hills, Montag and Pratt eloped in Mexico. Months later, the couple celebrated with family and friends in a made-for-TV wedding, which also aired on the show.

Following his wife's proclamation of wanting a baby, Pratt told cameras, "I'm baby blocking."

Marriage Boot Camp: Reality Stars premieres on Jan. 9 on WEtv. The show also includes Bad Girls Club's Natalie Nunn and her husband Jacob Payne, Survivor: Blood vs. Water's Tyson Apostol and Rachel Foulger, and R&B Divas' Syleena Johnson and her husband Kiwane Garris.

During the show, as seen in the video below, Montag and Pratt were forced to live in a nursery, which was due to serve as a constant reminder of the biggest issue in their marriage.

Tags: Heidi Montag Spencer Pratt