It was double joy yesterday for Ms Tin Pei Ling, the People's Action Party's (PAP) youngest MP.

Early in the morning, the 31-year-old gave birth to her first child: a son.

Later in the afternoon, Emeritus Senior Minister Goh Chok Tong made her wish come true when he personally delivered to her the party's decision: She will be fielded in single-seat MacPherson in the coming general election.

The electoral battle looks set to be fierce as the Workers' Party (WP) and National Solidarity Party have declared their intention to contest the single-member constituency carved out of Marine Parade GRC.

But Ms Tin is taking the prospect of juggling motherhood and preparing for the contest in her stride.

She told The Straits Times last night: "We have set up ground networks to ensure 'business as usual' even when I take a short confinement break.

"I believe MacPherson residents will also take a long-term perspective and see that... we will continue to represent their interests and improve their living environment."

Ms Tin announced the arrival of her jubilee baby with an exuberant Facebook post at 10am: "I'm happy to share that I've 'popped'! It's a healthy baby boy."

Later in the day, ESM Goh, who leads the Marine Parade GRC team, visited the mother and baby at Singapore General Hospital.

"Mother looks radiant and baby ruddy. Father is, of course, happy," he wrote on Facebook later, referring to Mr Ng How Yue, the Law Ministry's permanent secretary.

"Lest she is anxious, I passed the message from the party that she will be fielded in MacPherson in the coming GE."

Mr Goh said he advised her to rest and not worry about the GE date. He added: "There will be time for her to turn up (on) Nomination (Day) and campaign thereafter.''

Yesterday, Ms Tin's Facebook page was flooded with congratulatory messages from hundreds of netizens, including her party members.

Her fellow MPs in Marine Parade GRC told The Straits Times they would help in her constituency.

Said Dr Fatimah Lateef: "We've worked on the same team and will continue to support her in every possible way."

Mr Seah Kian Peng noted that Ms Tin had been hard at work throughout her pregnancy.

Last week, she ran her Meet-the-People session late into the night.

"I know she is eager to hit the ground running and serve her residents, but I also know her residents will likely want her to rest first,'' he said.