Wisconsin Gov. Scott Walker became the latest former Republican candidate to back Sen. Ted Cruz on Tuesday.

"I've said it on the campaign trail for governor and last July ... I think Americans want to know what you're for and not just what you're against," Walker said in an interview on Milwaukee radio station, Newsradio 620 WTMJ.

.@TedCruz is the best-positioned candidate to both win the Republican nomination and defeat Hillary Clinton. I’m proud to stand with him. — Scott Walker (@ScottWalker) March 29, 2016

"I just fundamentally believe ... that Ted Cruz is the best position by far to win the nomination of the Republican Party and go on to beat Hillary Clinton," he added.

Walker made his announcement one week ahead of the state's April 5 primary.

"Ted Cruz is a principled constitutional conservative who understands that power belongs to the states -- and to the people -- and not bureaucrats in Washington," Walker posted online.

His endorsement could prove crucial in the state. Cruz and Donald Trump are currently neck-in-neck according to the latest polling averages from Real Clear Politics, which find Trump with 32 percent support, Cruz with 30.3 percent, and Ohio Gov. John Kasich well behind with 16 percent.

Walker briefly sought the GOP nomination himself, entering the race last year and then becoming one of the first candidates to drop out in September after surging and quickly falling behind in the polls.

He joins a growing number of Republican leaders who have started throwing their support to Cruz in recent weeks, including Mitt Romney who endorsed Cruz shortly after appearing on the campaign trail with Kasich, arguing that Cruz had a better shot at both uniting the party and winning the required number of delegates.

Check out photos of Cruz and his wife, who has become a reluctant prominent figure in recent weeks:

20 PHOTOS Heidi Cruz See Gallery Scott Walker announces his support for Sen. Ted Cruz Republican presidential candidate Ted Cruz and wife Heidi wave to supporters during his Keep The Promise rally at the zMax Dragway in Concord, N.C., on Sunday, March 13, 2016. (David T. Foster III/Charlotte Observer/TNS via Getty Images) STAFFORD, TX - MARCH 1: Heidi Cruz laughs as her daughters, Catherine (L) and Caroline autograph two Dr. Seuss books during a Super Tuesday watch party for husband, Republican presidential candidate, Sen. Ted Cruz (R-TX), at the Redneck Country Club March 1, 2016 in Stafford, Texas. Cruz won the Texas, Oklahoma, and Alaska primaries. (Photo by Erich Schlegel/Getty Images) STAFFORD, TX - MARCH 1: Republican presidential candidate, Sen. Ted Cruz (R-TX) celebrates holding his daughter Catherine with his wife Heidi and daughter Caroline during a Super Tuesday watch party at the Redneck Country Club March 1, 2016 in Stafford, Texas. Cruz won the Texas, Oklahoma, and Alaska primaries. (Photo by Erich Schlegel/Getty Images) COLUMBIA, SC - FEBRUARY 20: Republican presidential candidate Sen. Ted Cruz (R-TX), his wife Heidi and daughter Catherine observe a moment of silence for the late U.S. Supreme Court Justice Antonin Scalia during a primary night party at the South Carolina State Fairgrounds February 20, 2016 in Columbia, South Carolina. Cruz and Sen. Marco Rubio (R-FL) are locked in a tight race for finishing second in the South Carolina GOP primary. (Photo by Alex Wong/Getty Images) COLUMBIA, SC - FEBRUARY 20: Heidi Cruz (R), wife of Republican presidential candidate Sen. Ted Cruz (R-TX), waves with daughters Caroline (2nd R) and Catherine (L) during a primary night party at the South Carolina State Fairgrounds February 20, 2016 in Columbia, South Carolina. Cruz and Sen. Marco Rubio (R-FL) are locked in a tight race for finishing second in the South Carolina GOP primary. (Photo by Alex Wong/Getty Images) Republican presidential candidate Ted Cruz's wife Heidi looks out from back stage during a campaign rally in Charleston, South Carolina, February 19, 2016. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Republican presidential candidate Ted Cruz (R) sits with his wife Heidi during a campaign rally in Charleston, South Carolina, February 19, 2016. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Heidi Cruz, right, wife of Senator Ted Cruz, a Republican from Texas and 2016 presidential candidate, left, grabs her husband's chin after kissing him on stage during his campaign's caucus night celebration at the Elwell Center on the Iowa State Fairgrounds in Des Moines, Iowa, U.S., on Monday, Feb. 1, 2016. Cruz won the Iowa Republican caucuses in an upset over billionaire Donald Trump, while Democrat Hillary Clinton was clinging to the narrowest edge over Senator Bernie Sanders of Vermont. Photographer: Luke Sharrett/Bloomberg via Getty Images WINDHAM, NH - FEBRUARY 02: Heidi Cruz (R), wife of Republican presidential candidate Sen. Ted Cruz (R-TX), talks with their daughter Caroline, 7, before a campaign town hall meeting at the Crossing Life Church February 2, 2016 in Windham, New Hampshire. Cruz emerged at the top of a crowded GOP presidential field after winning Monday's Iowa caucuses. (Photo by Chip Somodevilla/Getty Images) DES MOINES, IA - FEBRUARY 01: Republican presidential candidate Sen. Ted Cruz (R-TX) stands with his wife Heidi as he addresses supporters after winning at the caucus night gathering at the Iowa State Fairgrounds on February 1, 2016 in Des Moines, Iowa. Cruz beat out frontrunner Donald Trump and Marco Rubio (R-FL) to win the Iowa caucuses. (Photo by Christopher Furlong/Getty Images) DES MOINES, IA - FEBRUARY 01: Republican presidential candidate Sen. Ted Cruz (R-TX) embraces his wife Heidi in front of supporters at the caucus night gathering at the Iowa State Fairgrounds on February 1, 2016 in Des Moines, Iowa. Cruz beat out frontrunner Donald Trump and Marco Rubio (R-FL) to win the Iowa caucuses. (Photo by Christopher Furlong/Getty Images) WASHINGTON, USA - JANUARY 31: Wife of Republican Presidential Candidate Ted Cruz, Heidi Cruz, speaks during a campaign rally in Iowa City, Iowa, USA on January 31, 2016. Both Democratic and Republican candidates are campaigning in Iowa this weekend before the Iowa Caucus on Monday. (Photo by Samuel Corum/Anadolu Agency/Getty Images) Heidi Cruz, the wife of Republican Presidential Candidate Ted Cruz, has a laugh at the North Star Lounge during a campaign stop in Fenton, Iowa, January 29, 2016, ahead of the Iowa Caucus. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Heidi Cruz, the wife of Republican Presidential Candidate Ted Cruz, has a laugh at the North Star Lounge during a campaign stop in Fenton, Iowa, January 29, 2016, ahead of the Iowa Caucus. / AFP / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) FENTON, IA - JANUARY 29 : Republican presidential candidate Ted Cruz, center, listens as his wife Heidi Cruz, left, speaks during a campaign event at North Star Restaurant and Lounge Shop January 29, 2016 in Fenton, Iowa. Cruz, who is seeking the nomination for the Republican Party is on the presidential campaign trail across Iowa ahead of the Iowa Caucus taking place February 1, a week before the New Hampshire Primaries. Joshua Lott for The Washington Post via Getty Images DES MOINES, IA - AUGUST 21: Heidi Nelson Cruz, the wife of Republican presidential candidate Sen. Ted Cruz (R-TX), and thier daughter Catherine listen as Ted Cruz speaks to supporters at his Religious Liberty Rally on August 21, 2015 in Des Moines, Iowa. Earlier in the day Republican presidential candidate Sen. Ted Cruz (R-TX) visited and spoke to guests at the Iowa State Fair. (Photo by Scott Olson/Getty Images) Catherine Cruz, left, waves to her dad, Ted Cruz, a Republican from Texas and 2016 presidential candidate, as she sits on the lap of her mom Heidi Nelson Cruz at the Rally for Religious Liberty in Des Moines, Iowa, U.S., on Friday, Aug. 21, 2015. A day after Jimmy Carter appeared on national television to talk about the cancer that's ravaging his body, Republican presidential candidate Cruz criticized the former president's administration in a speech in Iowa. Photographer: Daniel Acker/Bloomberg via Getty Images DES MOINES, IA - AUGUST 21: Republican presidential candidate Sen. Ted Cruz (R-TX) sits with his wife Heidi Nelson Cruz at the Religious Liberty Rally he was hosting on August 21, 2015 in Des Moines, Iowa. Earlier in the day Republican presidential candidate Sen. Ted Cruz (R-TX) visited and spoke to guests at the Iowa State Fair. (Photo by Scott Olson/Getty Images) U.S. Senator Ted Cruz, a Republican from Texas, stands with his wife Heidi Nelson Cruz and daughters Catherine Cruz, left, and Caroline Cruz, right, as he marks the start of his presidential campaign by giving the convocation address at Liberty University in Lynchburg, Virginia, U.S., on Monday, March 23, 2015. By kicking off his campaign at the Virginia Christian college founded by the late evangelist Jerry Falwell, rather than a venue in his home state, Cruz is signaling hell court religious conservatives as well as small-government tea-party activists as he competes to become the lead anti-establishment candidate in the party contest. Photographer: Jay Paul/Bloomberg via Getty Images LYNCHBURG, VA - MARCH 23: U.S. Sen. Ted Cruz (R-TX) kisses his wife Heidi Cruz before walking onstage to speak at Liberty University to announce his presidential candidacy March 23, 2015 in Lynchburg, Virginia. Cruz officially announced his 2016 presidential campaign for the President of the United States during the event. (Photo by Mark Wilson/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Former candidate Jeb Bush also decided to throw his support behind Cruz shortly after the Utah vote.

The growing support for Cruz among establishment Republicans suggests that Trump may need to keep prepping his plan to battle in a possible contested GOP nominating convention this summer.

Walker said he plans to campaign for Cruz throughout the state before the April 5 Wisconsin primary.

More from AOL.com:

Supreme Court fight: Quarter of Republican senators now back meetings for Merrick Garland

New report shows millennial and minority voters face huge obstacles at the polls

Former Trump strategist calls him 'presidential equivalent of Sanjaya' on 'American Idol'