Kate Middleton is not slowing down even if she's already in the third trimester of her pregnancy.

On Wednesday, Middleton and Prince William joined forces to visit Sunderland in North East England for the official opening of the Fire Station. It's one of the iconic buildings in the city that was converted into an art hub.

During the outing, Middleton arrived in Seraphine's Phaedra Woven Maternity Dress. The Duchess of Cambridge got a henna tattoo from a local artist named Shajida Begum, 18, People reported.

Middleton was all smiles as Begum drew a brown flower with a swirl on her hand. The henna used in Prince William's wife is natural, which is solely derived from plants. It has no chemicals and is safe to use during pregnancy.

"After two days it will start disappearing slowly and after two weeks it will be gone completely. It just leaves an orange stain on the skin," said Kumareswaradas Ramanathas, project manager at Young Asian Voices of Middleton's bridal henna.

"I said, 'Would you like a design?' and she was like, 'Yes, if you don't mind,'" Begum told the reporters.

"She was saying that it was really pretty. I was just telling her how it works. I was telling her when she can wash it off — I said, 'When it becomes flaky.'"

Middleton reportedly asked for a pack of bindis too because her daughter, Princess Charlotte, wanted it. After getting her henna tattoo, Middleton slipped into hard hat and vest to visit the Northern Spire bridge over the River Wear, with Prince William. It is due to open later this spring.

In related news, Prince William and Middleton graced the BAFTAs red carpet together on Sunday. Middleton received an intense backlash in her forest green gown created by her favorite designer, Jenny Packham. Many were disappointed that the Duchess did not wear black to support the Time's Up movement and #MeToo campaign.

However, some understood Middleton and even defended her. Olivia Munn was one of those who believed that the Duchess should not be criticized just because she did not wear black at the event.

"The Times Up dress code suggestions should not be used to ostracize or control," Munn wrote on  Twitter. "What we stand for & what we fight for matters more than the color of our dress. I have a hard time believing that the Duchess of Cambridge doesn't stand beside us just because she was wearing green."