Princess Kate shows off her pregnant belly in stunning black lace dress at charity gala

Kate, 35, attended the gala for the mental health organization.

— -- Princess Kate hosted a charity gala Tuesday at Kensington Palace to benefit a mental health charity for which she serves as royal patron.

Kate, 35, who is expecting her third child in April, showed her baby bump in a stunning floor-length, black lace gown by designer Diane von Furstenberg.

Prince Harry's girlfriend, Meghan Markle, has been seen in a shorter version of the dress Kate wore Wednesday evening.

Kate, who is known for recycling some of her most elegant outfits, last wore the gown when she was expecting her 2-year-old daughter, Princess Charlotte, in 2014.

Kate, also the mother of Prince George, 4, has made limited appearances since announcing her third pregnancy in September.

Kensington Palace announced at the time that Kate was suffering from hyperemesis gravidarum, or severe morning sickness.

Kate has tried to stick to her schedule of engagements as her health allows, particularly for events that benefit young children and raise awareness for mental health.

She hosted an event today for Place2Be, a charity for which Kate also serves as royal patron. Place2Be provides in-house counselors and professionals to support adolescents suffering from mental health challenges, stress and anxiety.

"As a mother just getting used to leaving my own child at the school gates, it is clear to me that it takes a whole community to help raise a child," Kate said at today's forum. "Whether we are school leaders, teachers, support staff or parents, we're all in this together."

She added, "We are all working to give children the emotional strength they need to face their futures and thrive."

Tuesday's gala benefited the Anna Freud National Centre for Children and Families, an organization dedicated to mental health accessibility and treatment for young children in need. Kate has been a champion of better resources for maternal mental health and programs that support early intervention for vulnerable children and families.