ET's Katie Krause spoke with Harrison at KIIS FM's iHeart Radio Jingle Ball, presented by Capital One, in Los Angeles on Friday, where he teased what the Bachelor couple will be naming their baby on the way.
"I can't confirm this, but I heard the name is either Christina or Christopher," he joked. "After me."
"I told them Harrison would be OK too," he continued, before setting the record straight: "I'm making this up. This is not breaking news!"
Luyendyk and Burnham announced their pregnancy in November, just two months before they're set to tie the knot in Hawaii. The couple got engaged on "The Bachelor: After the Final Rose" in March, following Luyendyk's dramatic breakup with his ex-fiancee, Becca Kufrin.
"I was not surprised they're getting married. The baby announcement caught me off guard, but I'm unbelievably excited for them," Harrison told ET. "They built this life in Arizona, they have the new house, they put the pool in, they're just a cute couple. I love them to death and I'm glad that they have kind of gotten away and gotten back to their life. So I'm very, very happy for them."
So far, Luyendyk and Burnham appear to be doing their wedding their way, rather than televise their nuptials in a big Bachelor wedding. When asked if there's a chance he could officiate the ceremony, like he has for past Bachelor couples, Harrison answered: "I can't confirm or deny, but I think that would be fun, to go to Hawaii and officiate the wedding."
For now, Harrison is focused on Colton Underwood's upcoming season of "The Bachelor," which premieres in January. And for those fans still unsure about the season, Harrison might have an idea for the next Bachelor.