Summer will reignite her physical attraction to her ex-boyfriend by sharing a passionate kiss over the coming weeks.
Lucas told TV Week: "She's only thinking she wants him in that moment and not the ramifications it could have."
Of Summer's motives, the actress added: "It's the first time Summer has ever gone with her instincts on something like this.
"He was Summer's first true love, so she will always have a special place in her heart for him."
After Andrew recently cheated on Summer with university friend Belinda, the pair broke off their relationship.