The actress, 28, pulled on some grey leggings, a loose black T-shirt and a grey hoodie when she hit the gym in California on Tuesday (19 November).
Ashley added a touch of girly glamour to her work-out look with pink trainers and a pink sports bra.
The High School Musical star got engaged to rocker Christopher, from band Annie Automatic, in August after just eights months together.
As for her wedding plans, she recently admitted: "I want to make sure it's perfect! But it's going to be a while."
Ashley's even roped her man in to some of her workouts, as the couple went hiking around LA's Runyon Canyon earlier this month.
And on November 15, Ashley Tweeted about her trip to a well-known American gym. She said: "Equinox we meet again #sweatitout #dontstop #getitgetit."
She is clearly one bride-to-be on a mission!
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