Leclerc, who stars as hearing-impaired Daphne Vasquez on the ABC Family series, is engaged to marry her boyfriend, real-estate agent Brian Stuart Habecost.
"We are thrilled to start our life together,” Leclerc, who turns 27 on Wednesday, tells PEOPLE exclusively.
"We can't wait to combine families and start the adventure together."
Habecost, 29, recently popped the question by decorating their entire Los Angeles home with flowers, balloons and a banner that said, "Katie will you marry me?"
When she walked into the house, she saw the sign and immediately started to cry. Soon he got down on bended knee and proposed.
The couple plan to marry next fall.