Now this is one hot mama!
The former Saved by the Bell star rocked a red one-piece while lounging beachside and working on her tan. The birthday girl paired the swimsuit with a long gold necklace and her favorite pair of sunglasses.
E! News first reported that the White Collar actress was on a romantic getaway at the Viceroy Zihuantanejo, a luxury resort in Playa La Ropa, Guerrero, Mexico.
She and hubby Brady Smith were joined by her costar Willie Garson, brother Schuyler Thiessen and his wife.
The group enjoyed a special birthday dinner and celebration for the brunette beauty on the sand along the hotel's private beach.
Thiessen posted several pics on Instagram documenting the trip, including a snapshot of her birthday dinner. "A perfect evening for a dinner party #birthdayweekend," she wrote as the caption.
Partygoers dined on tenderloin, sea bass filet, au gratin potatoes, Mexican rice, shrimp, and sautéed spinach. For dessert, guests chose between chocolate fondant with macadamia ice cream or guava and passion fruit mousse.
The pic showed a table facing the ocean as the sun went down, with tiki torches and lights placed throughout the romantic dinner site.
She also shared an adorable picture with her husband hugging by a fire pit. The sweet photo was captioned, "My favorite guy #birthdayweekend #I'm40#beachsunset."