Although they are largely unseen, angels are real just like people, and they exist in great numbers, legendary evangelist Billy Graham said.

The 97-year-old preacher expounded on the reality of angels in this world in a reply to a question by a reader in the Q&A segment of his column in the Kansas City Star on Thursday, as reported by The Gospel Herald.

"What do angels look like? Do they look like the pictures we see on Christmas cards? Or are they even real?" the reader asked.

Graham replied, "Yes, angels are real, just as real as you and I are. Although they are largely unseen by us, they exist in great numbers. The Bible speaks of 'thousands upon thousands of angels in joyful assembly' (Hebrews 12:22). When Jesus' birth was announced to the shepherds outside Bethlehem, 'a great company of the heavenly host appeared ... praising God' (Luke 2:13)."

Graham said angels are a mystery to many people because they do not have physical bodies. However, he said, on occasion angels appear as ordinary humans or glorious celestial beings that reflect the majesty of God.

"When God gave the prophet Isaiah a vision of his glory, his throne was surrounded by angels of great splendour and power: 'At the sound of their voices the doorposts and thresholds shook"'(Isaiah 6:4)," he quoted from the Holy Bible.

But why did God create angels? Graham said the angels are here in this world to serve God. "They work in hidden ways to carry out God's will and protect God's people," he wrote.

"Even when we are unaware of them, they are still part of our lives. They also are part of a great unseen army that constantly fights against Satan and his servants of evil. God's promise should bring comfort to every believer: He will command his angels concerning you to guard you in all your ways' (Psalm 91:11)."

Although angels are godly creations, Graham said people should not worship angels, as God alone is worthy of worship.

"But we can thank God for them," he said, "and some day in heaven we'll realise just how much they've done for us, at God's command."

Despite the mystery surrounding angels, two-thirds of Americans (68 percent) completely or mostly agree that angels and demons are active in this world, according to a recent survey by the Pew Research Center.

Another noted evangelist, Saddleback Church pastor Rick Warren, also spoke about the reality of angels who, he said, comprise a powerful "invisible army of God" who are always on the side of Christians who trust in God even when all hope appears to be lost.