The former "Suits" actress flashed her black lace bra underneath her navy collared dress, which featured a pleated, multi-colored skirt by Club Monaco.
The Royal Family also celebrated Markle's birthday with messages on Twitter.
Meghan is reportedly planning to visit her father ahead of the royal couple's next worldwide tour. She started off on her wedding day in a gorgeous gown that gave off major Old Hollywood vibes.
The Queen is the only member of the royal family Meghan has a height advantage over.
Mr van Straubenzee, who works for investment management firm Brown Advisory, is marrying party and wedding videographer Daisy Jenks.
Oil supported as new hedges placed, but rising global…
Brent crude futures LCOc1 were down 13 cents, or 0.2 percent at $73.32 a barrel by 0052 GMT, after rising 1.5 percent on Thursday. Oil prices are also feeling the effects of tensions over global trade, which could cause economic growth to slow.
The 53-year-old has been an outspoken critic of her little sister in recent months, especially as Meghan's relationship with her father has become strained by his repeated comments about her to the press.
It's been a whirlwind year for Harry and Meghan, who tied the knot in May in front of the royal family and their celebrity friends.
Next spring, Meghan and Harry are scheduled to make their first tour to the United States at the request of the U.K. Foreign Office and the British government.
The royal couple, holding hands, left together shortly after the hour-long ceremony ended and sped off before the newlyweds were showered with confetti.
Meghan, 37, doesn't get much help when it comes to Wills' wife Kate either.
Harry also alluded to children being in the couple's future in an interview last November.