For a will to be valid, it must have both formal validity and essential validity. Formal validity asks whether the will is treated as properly executed under the applicable law. Essential validity asks whether the testator had testamentary capacity, knew and approved the contents of the will, and was free from undue influence or the effects of fraud. These are separate questions and each must be addressed.

Formal Validity

The governing formal-validity provision

The starting point is section 5(2) of the Wills Act 1838 (the “WA“). The exact relevant words provide that a will “shall be treated as properly executed if its execution conformed to the internal law in force“. The place-of-execution rule is stated in section 5(2)(a) of the WA: “in the territory where it was executed“.

A will executed in another country

Where a will was executed in another country, section 5(2)(a) of the WA applies. If the execution conformed to the internal law of that country, the will is treated as properly executed and is formally valid on this ground. The proponent must therefore identify the country of execution and prove the relevant internal law where that law is not Singapore law.

A will executed in Singapore

Where a will was executed in Singapore, formal validity is governed by section 5(2) of the WA. Singapore is the territory of execution, so the question is whether the execution conformed to the internal law in force in Singapore.

Note: Under section 5(9) of the WA, section 5 applies only to a will of a testator who died after 26 June 1992, whether the will was executed before or after that date.

Essential Validity

Essential validity has three separate limbs

The person propounding the will bears the legal burden of proving its essential validity. As held by the Court of Appeal in Chee Mu Lin Muriel v Chee Ka Lin Caroline (Chee Ping Chian Alexander and another, interveners) [2010] 4 SLR 373 (“Muriel Chee“) at [37], which applied the principle in Banks v Goodfellow (1870) LR QB 549, the test for essential validity consists of 3 limbs:

a. the testator must have mental capacity (i.e. testamentary capacity);

b. the testator must know and approve the contents of the will; and

c. the testator must be free from undue influence or the effects of fraud.

All 3 limbs must be proven (i.e., separately pleaded) to make out essential validity of the will.

Testamentary capacity

The common-law test requires the testator to understand the nature and effect of making a will, the general extent of the property being disposed of, and the claims of those who might reasonably expect consideration. The testator must not be affected by a disorder of the mind that poisons the affections, perverts the sense of right or prevents the exercise of natural faculties in disposing of the estate.

Capacity is decision-specific and time-specific. A diagnosis of dementia does not by itself prove incapacity, just as the absence of a diagnosis does not establish capacity. The relevant question is the testator’s ability when instructions were given and when the will was executed.

In Muriel Chee at [40] to [41] and [52], the Court of Appeal explained the evidential framework. The propounder bears the legal burden of proving capacity. Where the will was duly executed in ordinary circumstances, the testator was not known to suffer from a mental disability and the dispositions are rational, testamentary capacity is prima facie established. If an incapacitating mental illness is shown to have caused a prior loss of capacity, the inquiry is whether the illness continued to affect the testator at the time of execution.

The later decision in XBP v XBO [2025] SGHC(A) 15 at [40] to [48] and [65] to [78] confirms that the evidence must be assessed as a whole. A mental disability does not automatically establish incapacity. The evidence of persons who interacted with the testator can be as significant as medical evidence, while the party alleging a specific incapacitating illness bears the evidential burden of proving that allegation.

Knowledge and approval

A testator with capacity must also know and approve the contents of the particular will. Once testamentary capacity is established, a rebuttable presumption of knowledge and approval ordinarily arises. Under Muriel Chee at [46] to [47], that presumption does not arise where circumstances attending or relevant to the preparation and execution of the will raise a well-grounded suspicion that the will did not express the testator’s mind.

In Lian Kok Hong v Lian Bee Leng and another [2016] 3 SLR 405 at [58] to [59] and [65], the Court of Appeal stressed that suspicious circumstances are relevant to whether the testator knew and approved the document. Examples include a beneficiary’s unusual involvement in procuring the will, a radical and unexplained departure from an earlier scheme, language the testator could not understand, or a drafting process that did not reliably record the instructions.

Knowledge and approval is not the same as testamentary capacity. A testator may be capable of making a will but sign a document that does not reflect the instructions. Conversely, a carefully explained document cannot cure an absence of testamentary capacity.

Undue influence and fraud

Testamentary undue influence requires coercion that overbears the testator’s free will. Persuasion, appeals to affection, gratitude and even persistent requests do not suffice unless the resulting document expresses the influencer’s wishes rather than the testator’s own wishes.

There is no general presumption of undue influence merely because the relationship was one of trust and confidence. The person alleging testamentary undue influence bears the burden of proving it, usually through circumstantial evidence because the testator cannot testify. Fraud is distinct and includes deliberately deceiving the testator about the nature or effect of the will.

UWF and another v UWH and another [2021] 4 SLR 314 at [212] to [237] illustrates why a finding on testamentary capacity does not dispose of a separate allegation of undue influence. The issues carry different requirements even though the same facts may be relevant to both.

Yours sincerely,

Daryl