The popstar and fitness trainer, who are currently expecting their first child together, announced they were engaged in September. To mark U.S. Mother's Day on Sunday, Sam shared an update about their upcoming wedding ceremony on his Instagram Stories. "Our lives has been a real life fairytale (love heart) happy Mother's Day my soon to be queen (sic). Also The big day has been set! But nobody will know until the day after (ring emoji)." Britney also teased the nuptials on Sunday by sharing a snap of their new cat Wendy laying on top of a white tulle veil...