Jada Pinkett Smith has given Miley Cyrus advice about getting married young.

The 'Madagascar 3' star - who will celebrate her 15th wedding anniversary to Will Smith on Dec 31 - says that Miley, 19, and fiancé Liam Hemsworth, 22, must first have a good friendship base.

She told Us Weekly: "Learn how to be friends, especially when you are starting that young.

"Forever is a long time. When you are starting forever at 19 years old, and it is not to say that there is anything wrong with that, but it is just to know that what it is now and what it will be, it is just going to continue to transform and change."

The 40-year-old actress began her relationship with 'Men In Black 3' star Will at 23 years old and the couple have two children Willow and Jaden together.

She added: "You have to keep flexibility [in your relationship]. You have to be with someone you consider as a friend."

Miley showed off her engagement ring to waiters at a restaurant in Los Angeles on Wednesday.

The 'Can't Be Tamed' singer accepted Liam's marriage proposal last month and celebrated her forthcoming nuptials with a dinner at Hugo's in Studio City.