'Boy Meets World' Star Trina McGee Pregnant at 54

"Boy Meets World" star Trina McGee is celebrating a pregnancy, but because she happens to be 54 years old ... she's asking fans to send some good vibes for a successful birth.

The actress took to Instagram Monday to announce she's expecting her 4th child ... and, from the sounds of it, the news was an unexpected surprise.

In a post set to The Supremes' hit "Baby Love," Trina wrote ... "At the tender age of 54 I have found myself pregnant. Please bless us with your prayers for a safe delivery. Thank you."

As she continued, Trina explained she'd be taking a social media break ... thanking her fans for their well wishes in advance.

Trina had previously teased her pregnancy news by uploading a photo of herself in a halter top and skirt, where her bump was visible. After one fan commented on the baby belly, Trina responded with a simple, "Yup."

Trina, who is best known for playing Angela Moore opposite Rider Strong's Shawn Hunter on 'BMW' in the late '90s, seemed to have pregnancy on the brain in recent weeks.

ICYMI ... back in April, she posted about being pregnant while filming the sitcom's famous Halloween episode, writing ... "That time I played a teenager but in reality I was 6 months pregnant ..."

Trina previously welcomed 2 children with ex-husband Courtland Davis, who she was married to between 1991 and 2001. She later welcomed another child during a different relationship.

According to People, Trina has been married to fellow actor Marcello Thedford for the last 16 years ... originally meeting on the set for Sylvester Stallone's 1996 thriller, "Daylight."