Cruz is barnstorming Iowa this week. (AP Photo/Andrew Harnik)

DES MOINES, Iowa — A former spokeswoman for ex-Arkansas governor Mike Huckabee has joined Ted Cruz's presidential campaign, giving the Texas senator a key operative who worked for the last two winners of the Iowa caucuses.

Alice Stewart, who stepped down as Huckabee's communications director last month, is now working for Cruz's team, she said Monday. Her official title is senior adviser.

Stewart was also Huckabee's communications director during the 2008 cycle, when he won the Iowa caucuses. Four years later, she served as press secretary for former Pennsylvania senator Rick Santorum, who went on to win the Iowa caucus in 2012.

Stewart's hire by the Cruz campaign comes as the Texas senator has emerged as a front-runner for the Feb. 1 caucuses, while Huckabee has struggled to gain traction in the state whose nominating contest he easily won eight years earlier. Stewart's transition also arrives as her old boss and his allies sharpen their attacks on the Texas senator, hoping to undercut his conservative credentials in the homestretch to the caucuses.

Stewart is expected to accompany Cruz on his six-day, 28-county bus tour of Iowa, which is set to begin Monday morning. Like Cruz, Huckabee is also planning to barnstorm the Hawkeye State in January, planning to hold 150 events throughout the month.