Includes video report

You may do a double take when you see the latest commercial from the Kentucky Lottery.

Yup. Legendary actor Bob Newhart dusted off his Papa Elf costume from his turn in the Christmas blockbuster movie "Elf" to work with the Kentucky Lottery promoting its Holiday Gift Series Scratch-Off campaign.

The 88-year-old actor's popularity spans multiple generations thanks to his television work on "Newhart" and "The Bob Newhart Show," which aired in the 1970s and '80s. He was introduced to a younger audience in 2003 when he appeared with comedian Will Ferrell in "Elf."

"I really like the knickers I was able to wear," Newhart said of his costume in the commercial. "They're a lot more comfortable than the tights I wore in the film."

Wait, back up. So how — and why — did the legendary actor end up in a Kentucky Lottery commercial promoting a scratch-off game?

It all started with one (really good) advertising pitch.

In August, Chip Polston and Edie Frakes, both executives with Kentucky Lottery, sat down with its Louisville-based advertising agency, Bandy Carroll Hellige. Each year, the lottery teams up with the agency to create a commercial promoting the lottery's Holiday Scratch-Off game.

One pitch during the session stood out as the clear winner.

"North Pole Focus Group" would involve a group of elves deciding which gift people would most want to receive this holiday season. After a few silly gifts ideas are presented, Holiday Gift Scratch-Offs are picked as the best gift.

"At the conclusion to the pitch, the agency told us to imagine the head elf who is moderating the focus group is Bob Newhart dressed as Papa Elf from the movie," Frakes said. "At that point, the hair stood up on our arms. Having Bob Newhart as Papa Elf would really make the commercial a hit."

So, the team made it a reality.

Newhart was game to take part in the commercial because he is "very proud of his role in 'Elf' and he believes it will be his legacy because the movie is on it's way to becoming a holiday classic," Polston said.

Frakes and Polston, who flew to California to oversee the commercial shot in a production studio in West Hollywood, said they were surprised at how relaxed the commercial set was.

Newhart "drove himself to the set," Polston said. "There was no entourage, he didn't even think his agents needed to be there."

What's even more surprising is that when the actor was having his elf ears and makeup applied, "we found out that his grandparents lived in Maysville and Covington, Kentucky."

Newhart's role in the commercial didn't stop when the cameras stopped rolling.

Newhart "worked for an ad agency in Chicago before he became an actor and during the making of our commercial, he got very involved in the process," said Frakes. "He actually wrote one of the jokes in the spot and it's very funny."

Still wearing his costume, Newhart would shuffle over after each take in his elf shoes to watch the playback, often making suggestions about ways to improve the scene.

"When a comedy legend wants to weigh in and offers to help, you don't refuse," Polston said. "You absolutely take that feedback."

Polston was allowed to take footage behind-the-scenes at the commercial shoot, much of which will appear on The Kentucky Lottery's social media channels throughout the holiday season — so keep an eye out.

Newhart also signed 12 Holiday Gift Series Scratch-Offs, which will also be offered in a social media promotion.

Last year, the Kentucky Lottery sold 10 million Holiday Scratch-Off tickets and is predicting 20 million in holiday sales this year from the new promotion.

"People love to give Scratch-Offs as stocking stuffers and gifts and we've always done a special holiday commercial to coincide with the promotion," Polston said, "but this one knocks them all out of the ballpark."

VIDEO: Watch behind the scenes