ATLANTA, Ga – A huge day of campaigning is in store for many of the candidates seeking to become Georgia's next congressional representative.

Former U.S. Housing and Urban Development secretary Julian Castro is canvassing for Democrat Jon Ossoff, who has dominated the field of 18 candidates seeking to replace Tom Price in the 6th district since the race began.

Ossoff himself is meeting with volunteers and supporters at campaign offices in Marietta, Sandy Springs and Chamblee.

RELATED: Ossoff dominates GOP field in exclusive 11Alive poll

As yet another sign that the race continues to attract national attention, actor Samuel L. Jackson has recorded a radio ad, urging people to vote for a Democrat in the 6th district, a district that has been held by Republicans since 1978.

Jackson is the latest celebrity to endorse a Democrat in the race to replace Price, now President Donald Trump's secretary of the U.S. Department of Health and Human Services. Last month, as early voting began in the April 18 election, actress Alyssa Milano was canvassing votes for Ossoff.

RELATED: Alyssa Milano canvassing for Jon Ossoff

On the GOP side, Karen Giorno, a former senior advisor for the Donald Trump campaign, is making her second day of appearances with Bob Gray, a former Johns Creek city councilman who is battling for a runoff spot with another Republican, Karen Handel.

Former House Speaker and 6th district congressman Newt Gingrich is doing a robocall on Saturday, urging voters to choose another Republican in the race, state Sen. Judson Hill.

Hill has some of the race’s highest profile endorsements, including from U.S. Sen. Marco Rubio, but those haven’t translated into any polling success for the longtime state lawmaker.

Karen Handel, who, along with Gray, are vying for the No. 2 spot behind Ossoff, also picked up a national endorsement late last week. Maggie’s List, a federal political action committee dedicated to electing conservative women to federal office, endorsed Georgia's former secretary of state.

Handel has also been endorsed by dozens of mostly local elected officials, as well as former U.S. Sen. Saxby Chambliss.

“Maggie's List has been instrumental in helping conservative women get elected to federal office, and I'm honored to have their endorsement,” said Handel. “If I have the privilege of being the first female Republican member of Congress elected from Georgia, you can count on me to continue the fight for limited government and conservative principles.”

Low-polling GOP contender Amy Kremer was endorsed last week by national conservative talk show host Sean Hannity and Katrina Pierson, a former spokesperson and top aide to President Trump.

"Listen, you have been a champion out there hitting the pavement for all these years,” Hannity said. “It's people like you that I'd love to see in Congress and think you would do a great job … I hope you win!"

"I fully support and endorse my friend Amy Kremer in her bid for Congress,” Pierson said. ”Everyone claims to be #teamtrump but I know who actually was!"

The race has attracted national donors and attention, as Democrats see an opportunity to flip a solid GOP district that Trump carried over Hillary Clinton by less than two percentage points last November.

RELATED: White House chief strategist Steve Bannon following 6th district outcome

The only way to avoid a June 20 runoff would be if one candidate receives 50 percent-plus-one.

You can check your voter registration status by clicking here, which will lead you to the Georgia Secretary of State's My Voter Page.

The district includes portions of Atlanta, Brookhaven, Chamblee, Dunwoody, Doraville, Tucker, Sandy Springs, Roswell, Alpharetta, Johns Creek Milton and Mountain Park.

PHOTOS: 6th district congressional debate

11Alive has the web's most extensive coverage of the 6th district race, which can be found here.