Blake Shelton is building a good relationship with girlfriend Gwen Stefani’s three children, Life & Style magazine reported Wednesday. Shelton and Stefani are reportedly planning to get married by Christmas and the 46-year-old’s children will take part in the ceremony.

The magazine reported that the couple and the children — Kingston, 10, Zuma, 8, and Apollo, 2 — went on a private tour of the Cincinnati Zoo & Botanical Garden earlier this month.

“They really did look like a family,” a source told Life & Style. “Blake acted like he was Apollo’s dad.”

The magazine had reported earlier that the children will play an important role at Shelton and Stefani’s wedding ceremony during Christmas.

“Apollo wants to be the ring bearer, and the two older boys will be junior groomsmen with Blake,” a source said at the time. “Blake wants it to be really special, to show them coming together as a family.”

Shelton is also reported to be bearing the entire expense of the wedding that will be attended only by family and close friends.

Before their wedding day, Stefani and Shelton are reportedly working on prenuptial agreement.

“The prenup will dictate that their earnings remain separate,” another insider told Life & Style magazine at the time, adding that their total fortune is $225 million.

Neither of the two will ask for spousal support should they divorce, plus Stefani’s Beverly Hills mansion will remain under her name and Shelton will keep his Oklahoma ranch under his name, the report added.

“Blake said he didn’t want [a prenup], but Gwen wants to make sure they are both protected,” the source said, adding that the 46-year-old singer did not have the agreement with her ex-husband Gavin Rossdale.