Actor Tom Arnold is a first-time dad at 54 - his wife Ashley Groussman has given birth to a son.

The couple welcomed little Jax Copeland Arnold on Saturday morning (06Apr13).

The funnyman tells People.com, "We are still in a bit of shock. It has been a long journey and the healthy birth of our son is a miracle."

He then took to Twitter.com to share his happy news with his followers, writing, "Game Changer: Jax Copeland Arnold. 8lbs 12oz. Looking forward to being a 70 year old Little League Coach."

Arnold, who suffers from a low sperm count, previously revealed he and his wife have been trying to start a family since they married in 2009, and they consulted fertility doctors in 2011 in their bid to conceive.

The in vitro fertilisation treatment has been a success and the veteran star recently called the unborn baby his "miracle" child after yearning for years to become a father.

Groussman is Arnold's fourth wife. He was previously married to fellow comic, Roseanne Barr.