Gwen Stefani's boyfriend, Blake Shelton, will celebrate his 41st birthday on Father's Day, but will the singer be thinking of her ex-husband, Gavin Rossdale, as they enjoy his special day?

According to a report, Stefani is having mixed emotions when it comes to Sunday's events.

"Gwen is having some varied emotions this year when it comes to Blake's birthday since it lands on Father's Day," an insider told Hollywood Life on Wednesday. "Father's Day reminds her of Gavin [Rossdale]."

Stefani and Rossdale were married for 13 years before they parted ways in August 2015 after welcoming three children together, 10-year-old Kingston, eight-year-old Zuma and three-year-old Apollo.

In addition to her feelings about Rossdale, Stefani is said to be excited about her future with Shelton, who she began dating in late 2015, months after her divorce was confirmed.

"It also reminds her of the family she is starting with Blake because he is now getting into the role of step dad even with them not being officially married," the source said.

"So as much as she wants to celebrate Blake's birthday, she also has to think of Gavin that day and it's a little weird and gets her to be a little emotional," continued the insider. "But Blake is taking things as they come with humor. He's putting her at ease saying that all they have to do is be together and he will be there for her regardless of what emotions she has on that day. He respects Gavin as the father of her kids and knows he will be in the picture forever so he is okay with Gwen's feelings and will do his best to make her not worry about it as much."