It's official. Deputy Prime Minister (DPM) Heng Swee Keat will be Singapore's Prime Minister — at least between Dec. 25, 2019 and Jan.3, 2020.

Prime Minister Lee Hsien Loong is officially on leave between Dec. 21, 2019, and Jan. 3, 2020, according to a statement from the Prime Minister's Office released on Friday afternoon.

Heng, being the only DPM, is the natural candidate to be appointed acting PM.

Wait, so who is acting PM before Christmas?

Observers would notice that there is a period of four days (Dec. 21 to 24) where PM Lee is on leave, yet there is no acting PM appointed.

PM's Press Secretary told Mothership in response to queries that PM Lee will still be contactable between Dec. 21 to Dec. 24, so there is no need for an acting PM.

Heng will then take over as PM for the remainder of his leave period, between Dec. 25, 2019, to Jan. 3, 2020.

It is normal for DPM to be appointed acting PM, when the PM is away either on work trips or on personal leave.

Heng was appointed acting PM for the first time in June 2019, when PM Lee was on leave.

He took over for a period of seven days then, between June 10 to June 16.

This would make Heng's upcoming stint as acting PM his longest yet, for a period of 10 days.

And where is PM Lee?

Like many Singaporeans, PM Lee's likely taking a break during the year-end holidays.

Earlier this year, he took leave in June to spend time with his family and catch up on his reading.

His plans for this vacation period, though, aren't immediately clear — whether he'll be travelling or staying home for a bit.

Although he hinted at what he would be up to in a Facebook post he put up at about 6pm:

"I will be on leave for the rest of the year. Will spend some time trying to decipher Tao’s method. Also plan to catch up on my other readings, spend time with family, and perhaps go #jalanjalan (if the rain stays away)."

But this not-so-common scenario of being contactable while on leave goes to show you: even PM Lee can't escape the woes of responding to work matters while he is on leave.

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Top images from Heng Swee Keat's Facebook/MCI and Lee Hsien Loong's Facebook/MCI.