Kate and husband William are scheduled to help welcome the President of Singapore Tony Tan Keng Yam to London on behalf of Queen Elizabeth later this month.
The expectant mom has not been seen in public since the Sept. 8 announcement of her pregnancy and she became ill with severe pregnancy sickness, hyperemesis gravidarum.
Mindful of Kate's ongoing struggle with the effects of her current condition, a palace source tells PEOPLE that Kate "very much hopes to be able to undertake this engagement, but as with all recent engagements her attendance will be reviewed closer to the time, depending on her health."
The President of Singapore event is set for Oct. 21 at London's Royal Garden Hotel – a short distance from Kate and William's Kensington Palace home.
The couple will then travel with President and Mrs. Tan to the Horse Guards Parade, where the visiting dignitary will receive a ceremonial welcome.
Kate and William visited Singapore during their 2012 tour to help celebrate the Queen's Diamond Jubilee.