The Duchess of Cambridge budled up for an official trip to London’s Baker Street tube station today (March 20th), joining Queen Elizabeth and the Duke of Edinburgh to celebrate the Underground’s 150th anniversary.
Inside the station, a particular train was named in Her Majesty’s honor, which boasts air-conditioned walk-through trains, according to the Daily Express‘s Richard Palmer.
Catherine dressed her bump in a Marlene Birger beaded coat with back pleating, and accessorized with a black pillbox hat she wore to Harry Aubrey-Fletcher‘s wedding in January 2011.
Palmer reports that Catherine asked the Queen and Prince Philip if she could join them on their engagement. Both households compared diaries and then the Queen formally extended an invite.
“She just fancied it,” a royal aide told Palmer. ”She asked if she could come along,”
Down on the tube station platform, the Duchess was gifted with a “Baby On Board” button, which are given out free to expectant mothers to wear. That way, they don’t have to ask a fellow tube ride to give up their seat.
This is Catherine and and Queen Elizabeth’s third engagement together. The Queen had been struck with a bout of gastroenteritis earlier this month and had to be hospitalized.