(CNN)Roger Federer has taken time out from his Turkey adventure to congratulate the British royal family on its latest addition.
Roger Federer tweets congrats to royals after birth of second baby
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The tennis superstar, who has four children, cheekily tweeted his message with the hashtags "#SlowlyCatchingUpToUs" and "2MoreToGo."
"Congratulations to the Duke and Duchess of Cambridge!" Federer posted on Saturday after reaching the final of the inaugural Istanbul Open.
Prince William and wife Catherine now have a baby daughter along with Prince George, who was born in 2013.
Federer and his wife Mirka have had two sets of twins -- the first, in 2009, were girls and then came two boys last year.
The 17-time grand slam champion will face 23rd-ranked Uruguayan Pablo Cuevas in his fourth ATP Tour final this season, and the 128th of his glittering career.
Federer, seeking his 84th tournament success, defeated eighth seed Diego Schwartzman 2-6 6-2 7-5 in the clay event.
"I think what was important in the third set was to keep working hard," said the world No. 2, who is aiming to win a title in a 19th different country. "I needed to put in a lot of effort to stay with Diego.
"Cuevas is playing very, very well... I think it's going to be a tough match. Cuevas has obviously played a lot on clay."
Cuevas ended the hopes of Grigor Dimitrov, who as a junior was known as "Baby Federer" due to his playing style.
He beat the Bulgarian second seed 6-2 6-4 to reach his fourth career final, having earned his third title in Sao Paulo in February.
"I come from a small country, and I'm used to having the crowd against me," said the 29-year-old. "Playing Roger tomorrow will be like playing Roger in his hometown."
Federer took time out earlier this week to do some sight-seeing, visiting both the Asian and European sides of the city.
"For me, it's been a joy traveling and going to see new places," said the Swiss. "I felt like a tourist. I still feel like I'm so young, and still able to discover new places. I think it's probably one of the reasons I'm still playing tennis today."
Meanwhile, Andy Murray is seeking to lift his first trophy as a married man after winning two matches in a day to reach the Munich Open final.
The two-time major champion, who wed longtime partner Kim Sears last month, first beat Czech Lukas Rosol 4-6 6-3 6-2 in a rain-delayed quarterfinal and then defeated Roberto Bautista Agut 6-4 6-4.
Afterwards he was quick to laugh off a magazine mistakenly claiming he is due to become a father -- it put his name in a headline to a story confirming that former tennis ace Andy Roddick and wife Brooklyn Decker are expecting.
In the first clay final of his career, Murray will take on home hope Philipp Kohlschreiber, who has won the tournament twice and been runner-up once.
The German also had to play twice, beating qualifier Gerald Melzer 2-6 6-1 6-4 after another three-setter against David Goffin.
"He's No. 3 in the world and a great champion. He's the favorite," 26th-ranked Kohlschreiber said of Murray, who is working with a new coach in former Swedish star Jonas Bjorkman.
"I have the home crowd and my surroundings. I'm going to need a pretty good day to beat him."