Tim Allen was concerned his TV romance could seem 'creepy'

Tim Allen was concerned his age-gap romance for TV show Shifting Gears would appear "creepy" to viewers.

The 72-year-old actor stars as Matt, the stubborn widowed owner of a classic car restoration shop in the popular US sitcom.

Fans of the show were introduced to a blossoming romance between Matt and Eve, played by Jenna Elfman, in season one.

When Allen first saw the script, he feared the relationship could raise eyebrows because Jenna is almost 20 years younger than him.

"It gets creepy for me at a certain age (and) we're right at that border," he explained in Us Weekly's latest cover story.

"If Jenna didn't look so damn nice than our age gap is not that much. I just let my hair go natural and she just looks - especially on camera - quite young."

Allen went on to recall how he initially felt concerned after watching early scenes between Matt and Eve.

Despite the show bosses attempts to reassure him, Allen took some time to convince.

"They say when you're lit better and I go, 'When I'm lit better, I look probably 68,'" he joked.

"There's times - and I'll give it to them - that they lit right and in the right clothing so it doesn't look creepy."

He also acknowledged the age gap between himself and 54-year-old Jenna "is not much different" than his real-life marriage to Jane Hajduk, who is 59.

Despite his initial doubts, the Toy Story 5 star is thrilled to have Jenna in the show and is excited to see what awaits the couple in season three.

"She's so fun to be around and it's brought out a whole different part of that show and brought a different audience to that show," Allen explained as he praised Jenna.

"My question is - and we haven't talked about it yet... - is Jenna going to move in with me or am I going to move in with her (on the show)? I don't know. I'd like to stretch it out where we're just dating a little bit."