The actor's wife Kimberly Brook gave birth to baby Olivia on Saturday (25Sep10) and Van Der Beek announced the news via his Twitter.com page.
In a series of posts, he wrote, "Had the blessing of becoming a father over the weekend... Couldn't come close to describing this bliss even if I had 140 million characters... I apologise in advance for any obnoxiously precious new-dad Tweets that may follow. I'm under her spell..."
The 33-year-old star wed Brook last month (Aug10). He was previously married to actress Heather Ann McComb.